Hello there, ahmed-nagy,

There are five types of users you can add to QuickBooks. If you want to customise the access level of a user, you'll want to use Standard user.

• Standard user
• Company admin
• Reports only
• Time Tracking only
• Accountant

With Standard user access, you can customise their access rights with these:

• All
• None

• Limited - Customers & Sales

• Limited - Suppliers & Purchases

Here's how you can add them:

1. Select Settings.
2. Select Manager Users.

Check this article for more information: User types in QuickBooks Online.

Stay in touch with me if you need anything else.

@ahmed-nagy 

As another option, consider having a CRM app for your sales team and integrate it with your QBO. They don't need to have any access to QBO.