diff --git a/custom_fields/__init__.py b/custom_fields/__init__.py
index e69de29bb..9a7e03ede 100644
--- a/custom_fields/__init__.py
+++ b/custom_fields/__init__.py
@@ -0,0 +1 @@
+from . import models
\ No newline at end of file
diff --git a/custom_fields/__manifest__.py b/custom_fields/__manifest__.py
index 6d0c83768..f68cdc70c 100644
--- a/custom_fields/__manifest__.py
+++ b/custom_fields/__manifest__.py
@@ -1,15 +1,16 @@
 {
-    'name': 'Deal Eligible Management',
+    'name': 'Custom sale and invoice fields',
     'version': '1.0',
     'summary': 'Module to manage deal eligibles',
     'description': 'Custom module for managing deals and their details in Sales Management.',
     'author': 'Your Name',
     'website': 'https://yourwebsite.com',
     'category': 'Sales',
-    'depends': ['base', 'sale', 'account'],
+    'depends': ['base', 'sale', 'account','purchase',],
     'data': [
         'security/ir.model.access.csv',
-        'views/deal_eligible_views.xml',
+        'views/sale_order_views.xml',
+        'views/account_move_views',
     ],
     'installable': True,
     'application': True,
diff --git a/custom_fields/models/__init__.py b/custom_fields/models/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/custom_fields/models/account_move.py b/custom_fields/models/account_move.py
new file mode 100644
index 000000000..f5a26dd30
--- /dev/null
+++ b/custom_fields/models/account_move.py
@@ -0,0 +1,61 @@
+from odoo import api, fields, models
+
+class AccountMove(models.Model):
+    _inherit = 'account.move'
+
+    booking_date = fields.Date(
+        string='Booking Date',
+        tracking=False,
+    )
+    
+    developer_commission = fields.Float(
+        string='Broker Commission',
+        tracking=True,
+    )
+    
+    buyer = fields.Many2one(
+        'res.partner',
+        string='Buyer Name',
+        tracking=True,
+    )
+    
+    deal_id = fields.Integer(
+        string='Deal ID',
+        tracking=True,
+    )
+    
+    project = fields.Many2one(
+        'product.template',
+        string='Project Name',
+        tracking=True,
+    )
+    
+    sale_value = fields.Monetary(
+        string='Sale Value',
+        tracking=True,
+    )
+    
+    unit = fields.Many2one(
+        'product.product',
+        string='Unit',
+        tracking=True,
+    )
+
+    @api.model
+    def create(self, vals):
+        # Check if invoice is created from sale order
+        if vals.get('move_type') in ['out_invoice', 'out_refund'] and vals.get('invoice_origin'):
+            sale_order = self.env['sale.order'].search([
+                ('name', '=', vals.get('invoice_origin'))
+            ], limit=1)
+            if sale_order:
+                vals.update({
+                    'booking_date': sale_order.booking_date,
+                    'developer_commission': sale_order.developer_commission,
+                    'buyer': sale_order.buyer.id if sale_order.buyer else False,
+                    'deal_id': sale_order.deal_id,
+                    'project': sale_order.project.id if sale_order.project else False,
+                    'sale_value': sale_order.sale_value,
+                    'unit': sale_order.unit.id if sale_order.unit else False,
+                })
+        return super(AccountMove, self).create(vals)
\ No newline at end of file
diff --git a/custom_fields/models/custom_fields.py b/custom_fields/models/custom_fields.py
deleted file mode 100644
index 2fb86e998..000000000
--- a/custom_fields/models/custom_fields.py
+++ /dev/null
@@ -1,14 +0,0 @@
-from odoo import models, fields, api
-
-class DealEligible(models.Model):
-    _name = 'deal.eligible'
-    _description = 'Deal Eligible'
-
-    booking_date = fields.Date(string="Booking Date")
-    developer_commission = fields.Float(string="Broker Commission", tracking=True)
-    buyer = fields.Many2one('res.partner', string="Buyer Name", tracking=True)
-    deal_id = fields.Integer(string="Deal ID", tracking=True)
-    project = fields.Many2one('product.template', string="Project Name", tracking=True)
-    sale_value = fields.Monetary(string="Sale Value", tracking=True, currency_field='currency_id')
-    unit = fields.Many2one('product.product', string="Unit", tracking=True)
-    currency_id = fields.Many2one('res.currency', string="Currency")
\ No newline at end of file
diff --git a/custom_fields/models/sale_order.py b/custom_fields/models/sale_order.py
new file mode 100644
index 000000000..4be519b8c
--- /dev/null
+++ b/custom_fields/models/sale_order.py
@@ -0,0 +1,54 @@
+from odoo import models, fields, api
+from odoo.exceptions import ValidationError
+
+class SaleOrder(models.Model):
+    _inherit = 'sale.order'
+
+    # Custom fields for deal tracking
+    booking_date = fields.Date(
+        string='Booking Date',
+        tracking=True,
+    )
+
+    developer_commission = fields.Float(
+        string='Broker Commission',
+        tracking=True,
+        digits=(16, 2),
+    )
+
+    buyer_id = fields.Many2one(
+        'res.partner',
+        string='Buyer',
+        tracking=True,
+    )
+
+    deal_id = fields.Integer(
+        string='Deal ID',
+        tracking=True,
+        copy=False,  # Don't copy when duplicating record
+    )
+
+    project_id = fields.Many2one(
+        'product.template',
+        string='Project Name',
+        tracking=True,
+    )
+
+    sale_value = fields.Monetary(
+        string='Sale Value',
+        tracking=True,
+        currency_field='currency_id',
+    )
+
+    unit_id = fields.Many2one(
+        'product.product',
+        string='Unit',
+        tracking=True,
+        domain="[('product_tmpl_id', '=', project_id)]",  # Only show units related to selected project
+    )
+
+    @api.onchange('project_id')
+    def _onchange_project_id(self):
+        """Clear unit selection when project changes"""
+        if self.project_id:
+            self.unit_id = False
\ No newline at end of file
diff --git a/custom_fields/views/account_move_views.xml b/custom_fields/views/account_move_views.xml
new file mode 100644
index 000000000..f9211233f
--- /dev/null
+++ b/custom_fields/views/account_move_views.xml
@@ -0,0 +1,26 @@
+<!-- views/account_move_views.xml -->
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <record id="view_move_form_inherit_custom_fields" model="ir.ui.view">
+        <field name="name">account.move.form.inherit.custom.fields</field>
+        <field name="model">account.move</field>
+        <field name="inherit_id" ref="account.view_move_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//field[@name='partner_id']" position="after">
+                <field name="buyer" attrs="{'invisible': [('move_type', 'not in', ['out_invoice', 'out_refund'])]}"/>
+            </xpath>
+            
+            <xpath expr="//field[@name='payment_reference']" position="after">
+                <field name="booking_date" attrs="{'invisible': [('move_type', 'not in', ['out_invoice', 'out_refund'])]}"/>
+                <field name="deal_id" attrs="{'invisible': [('move_type', 'not in', ['out_invoice', 'out_refund'])]}"/>
+            </xpath>
+            
+            <xpath expr="//field[@name='invoice_date']" position="after">
+                <field name="project" attrs="{'invisible': [('move_type', 'not in', ['out_invoice', 'out_refund'])]}"/>
+                <field name="unit" attrs="{'invisible': [('move_type', 'not in', ['out_invoice', 'out_refund'])]}"/>
+                <field name="sale_value" attrs="{'invisible': [('move_type', 'not in', ['out_invoice', 'out_refund'])]}"/>
+                <field name="developer_commission" widget="percentage" attrs="{'invisible': [('move_type', 'not in', ['out_invoice', 'out_refund'])]}"/>
+            </xpath>
+        </field>
+    </record>
+</odoo>
\ No newline at end of file
diff --git a/custom_fields/views/custom_sale_fields_views.xml b/custom_fields/views/custom_sale_fields_views.xml
deleted file mode 100644
index 595e7acf3..000000000
--- a/custom_fields/views/custom_sale_fields_views.xml
+++ /dev/null
@@ -1,48 +0,0 @@
-<odoo>
-    <record id="view_deal_eligible_tree" model="ir.ui.view">
-        <field name="name">deal.eligible.tree</field>
-        <field name="model">deal.eligible</field>
-        <field name="arch" type="xml">
-            <tree>
-                <field name="booking_date"/>
-                <field name="developer_commission"/>
-                <field name="buyer"/>
-                <field name="deal_id"/>
-                <field name="project"/>
-                <field name="sale_value"/>
-                <field name="unit"/>
-            </tree>
-        </field>
-    </record>
-
-    <record id="view_deal_eligible_form" model="ir.ui.view">
-        <field name="name">deal.eligible.form</field>
-        <field name="model">deal.eligible</field>
-        <field name="arch" type="xml">
-            <form>
-                <sheet>
-                    <group>
-                        <field name="booking_date"/>
-                        <field name="developer_commission"/>
-                        <field name="buyer"/>
-                        <field name="deal_id"/>
-                        <field name="project"/>
-                        <field name="sale_value"/>
-                        <field name="unit"/>
-                    </group>
-                </sheet>
-            </form>
-        </field>
-    </record>
-
-    <menuitem id="menu_deal_eligible_root" name="Deal Management" sequence="10"/>
-
-    <menuitem id="menu_deal_eligible" name="Deal Eligibles" parent="menu_deal_eligible_root" action="action_deal_eligible" sequence="10"/>
-
-    <record id="action_deal_eligible" model="ir.actions.act_window">
-        <field name="name">Deal Eligibles</field>
-        <field name="res_model">deal.eligible</field>
-        <field name="view_mode">tree,form</field>
-    </record>
-</odoo>
-'''
diff --git a/custom_fields/views/sale_order_views.xml b/custom_fields/views/sale_order_views.xml
new file mode 100644
index 000000000..4db8bb31f
--- /dev/null
+++ b/custom_fields/views/sale_order_views.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<odoo>
+    <record id="view_order_form_inherit_deal_tracking" model="ir.ui.view">
+        <field name="name">sale.order.form.deal.tracking</field>
+        <field name="model">sale.order</field>
+        <field name="inherit_id" ref="sale.view_order_form"/>
+        <field name="arch" type="xml">
+            <xpath expr="//group[@name='sale_info']" position="after">
+                <group string="Deal Information">
+                    <field name="booking_date"/>
+                    <field name="developer_commission"/>
+                    <field name="buyer_id"/>
+                    <field name="deal_id"/>
+                    <field name="project_id"/>
+                    <field name="sale_value"/>
+                    <field name="unit_id"/>
+                </group>
+            </xpath>
+        </field>
+    </record>
+</odoo>
\ No newline at end of file