If you want to forward emails to your Pipedrive inbox from an email address other than the one you use to log into Pipedrive with, you will have to add that email address as an Alternate email address for Smart BCC.
To add an Alternate email address, go to Personal preferences > Email sync > Alternate email address for Smart BCC.
Validating the Alternative email address
Adding an email address as an Alternative email address will send a confirmation email to the added email address. This email will need to be validated before that address can be used successfully as an alternative email address in Pipedrive.
After the Alternative email address has been validated, you can start forwarding emails from this email address. Emails forwarded to the company-specific universal BCC address will show up in the Pipedrive inbox of the Pipedrive user who added that email address as an Alternative email address.