How can I put a signature on the letters?

How can I put a signature on the letters?

Since it is not required to have a signature on a dispute letter, we currently don’t have a feature to add a signature on the dispute letters automatically. If you need to add one, you can add it to the letter template as an image.

You will need to edit the letter while you're creating your disputes in the Dispute Manager Screen or under Company>Letter Vault. You will see a feature to upload and add an image to the letter template.