Navigate to the Signatures Tab and click the “New Signature” button.
When clicking the new signature button, you will be prompted to enter a display name and email address for the new signature. Don’t worry, these details won't be used for the signature itself and you can change these settings later.
You will also be asked to place the new signature into a group, so you can either create a new group or select from one of your existing groups.
Remember, if you have previously applied fields at the group level, this will apply to all new signatures too. For example, if you have applied the “Company” field to the group, that field will apply to the new signature.