Question: how to change email signature on galaxy s8?
Answer: From a Home screen, touch and swipe up or down to display all apps. ... 
Tap Email .
From an Inbox, tap the Menu icon. ... 
Tap the Settings icon (upper-right).
Tap the appropriate account.
Tap the Signature switch to enable or disable .
Tap Signature.
Edit the signature then tap DONE (upper-right).