It appears you need to copy and paste the desktop email signature from an email to use on the Thunderbird mobile app rather than the html version in the settings. I have copied and pasted my email signature from an email and tried using the Samsung flow app to copy it to clipboard. Both ways don't bring across images or coloured text and I can't see where to add/ edit either. Is there a way to add images or colour the text on the android mobile version of the Thunderbird email signature?