Assuming you have a US PayPal Business Account, there's a feature called Multi-User Access. You have to login to your PayPal Account Profile to setup everything. Note, you assign a User ID (not an email address) and a Password to each individual you want to add. After that, you can assign rights or permissions for access control. The users then use the User ID and Password you assigned to them so they can login. (Users cannot change their assigned ID and/or PW, only you can do that.)
See this guide for more info and details:
https://www.paypalobjects.com/webstatic/en_US/developer/docs/pdf/pp_merchantsetupadministrationguide...
