Hi mohamed fouad,

Example code for creating groups in pos (in XML file)

<record id="group_pos_user" model="res.groups">

   <field name="name">User</field>

   <field name="category_id" ref="base.module_category_sales_point_of_sale"/>

</record>

<record id="group_pos_manager" model="res.groups">

   <field name="name">Administrator</field>

   <field name="category_id" ref="base.module_category_sales_point_of_sale"/>

   <field name="implied_ids" eval="[(4, ref('group_pos_user')), (4, ref('stock.group_stock_user'))]"/>

   <field name="users" eval="[(4, ref('base.user_root')), (4, ref('base.user_admin'))]"/>

We can see the created groups from settings > Users & companies >Groups

Example code for access rights in pos (in CSV file)

Id,name,model_id:id,group_id:id,perm_read,perm_write,perm_create,perm_unlink
Access_pos_order_line,pos.order.line,model_pos_order_line,group_pos_user,1,1,1,1
access_account_payment_method_pos_user,account.payment.method pos_user,account.model_account_payment_method,group_pos_manager,1,0,0,0

To know more about security and security groups you can refer our following blogs
https://www.cybrosys.com/blog/security-in-odoo

https://www.cybrosys.com/blog/how-to-create-security-group-odoo-13

Regards