A PayPal account can have up to eight email addresses, any of which can be used to login to the account or receive payments. Your customers can see the email address used to receive payments so you should use a suitable one.
To add email addresses in PayPal, go to Profile, Add or Remove Email. Each new address has to be verified. To use a secondary PayPal email address with Payage, you must specify the account primary address in the "Account Primary Email" field of the account edit screen. Payage needs this to successfully match incoming payments.
Using secondary email addresses is a good way to keep track of payments from different sources. In PayPal, you can view payments made to each email address separately.