I recommend you reading carefully Odoo's documentation about users.

https://www.odoo.com/documentation/18.0/applications/general/users.html

I assume you know that creating a user can cause Odoo to charge you.

I advise you to create the user, assign a password to it, and then log in to Odoo with this new user. Then you can see what kind of access you are granting. Of course, you shouldn't give it any permissions from those belonging to the "Administration" group.

When you need to close access, simply "archive" the user.