To give access to the CRM module to a salesperson without granting full access to the entire Accounting or other modules, you can manage permissions using user roles and access rights in Odoo.

Steps to Set Up CRM Access Without Full Account Access:
Create a New User:

Go to Settings > Users & Companies > Users.
Click Create to add a new user for the salesperson.
Assign the User to a Sales Role:

Under the Access Rights tab, you can choose predefined roles for the user.
Assign the Salesperson role to the user, which gives access to the CRM, Sales Orders, Opportunities, and other related sales features.
Restrict Access to Accounting:

In the Access Rights tab, make sure to remove access to Accounting, Invoicing, or any other modules that you do not want the salesperson to have access to.
If the salesperson needs specific permissions in the Accounting module (e.g., to view invoices related to their sales), you can define more granular access by creating a custom group or role.
Use Record Rules for Granular Control (Optional):

If you need more specific control over what the salesperson can see and edit in CRM, use Record Rules.
Go to Settings > Technical > Security > Record Rules and create a rule to restrict or allow access to records in the CRM module based on the salesperson’s user ID or other conditions.
Confirm the Permissions:

Save the user settings, and the salesperson will only have access to the CRM and other sales-related modules based on the role you assigned, without full access to accounting or other modules.