Yes, you can! To add users to your Printful account, or to modify the user roles, go to your Printful dashboard then to settings and then click users. There are three roles that you can assign to new users: Admin, Manager, and Designer. In that section, you’ll also find the full list of permissions for user roles.
Note that all Admins can change the roles anytime in the account settings and it’s possible to have access to only one Printful account per email. So if the person you want to add to your account already has access to another Printful account, they need to use a different email address to be added to your account.