text: how to ad a signature to my email account? @yahoo?   ok so when you’re in the main mail account you click on options (to the right above the search bar). then, you look under "management" (second column) and find "signature" (it is blue, forth down) and click on it. after that you type in what you want as your signature and save it. if you want your signature on all outgoing messages click on the box with "add signature to all outgoing messages" beside it (near the bottom).