7.3.2. Specifying multiple user IDs

You might desire to use more than one email address to send secure email from. In this case, you do not need to generate one key pair for each address: you may simply associate multiple email addresses to your key pair. This will save you from the burden of managing multiple key pairs.

Select your key pair and choose Edit → Manage User IDs from Key Management, or choose Manage User IDs from the Key Properties of your key.

A window will pop up to show you a list of all user IDs (primary user ID and all additional user IDs) that are currently associated with the key. If this is the first time you perform this operation, your key will have only a primary user ID.

The Add and Delete buttons add and delete other user IDs. A user ID is composed of a name and email address; it is also possible to put an optional comment.
The Set primary button sets the selected user ID as primary, and as a consequence the previous primary user ID is relegated to the role of additional user ID.
The Revoke button revokes the selected user ID, which is then greyed out and deactivated. The difference with deletion is that a revoked user ID is still associated with the key pair but no longer usable.

Click on Close window to save the changes you have made to the key and to return to Key Management.

All user IDs are included in the public key when it is sent or exported. There is no mechanism in OpenPGP for selecting which user IDs are included and which not. This also applies to the PhotoID, which is a special type of user ID.