User IDs allow multiple identities and e-mail addresses to be used with the same key. Adding a user ID is useful, for example, when you want to have an identity for your job and one for your friends. They take the following form:
Name (COMMENT) <E-MAIL>
Click Applications › Utilities › Passwords and Keys.
Double-click the PGP key you want to view or edit.
Click the Names and Signatures tab, then click Add Name.
Specify a name in the Full Name field.
You must enter at least five characters in this field.
Specify an e-mail address in the E-Mail Address field.
Your e-mail address is how most people will locate your key on a key server or other key provider. Make sure it is correct before continuing.
In the Key Comment field, specify additional information that will display in the name of your new ID.
This information can be searched for on key servers.
Confirm your changes and enter the passphrase when prompted for it.