To ensure that signatures are not added to replies or forwards, you need to disable the option “Insert signature on reply/forward“.
To ensure that signature are added to replies or forwards, you need to enable the option “Insert signature on reply/forward“.
This option controls whether the signature is added in a reply or not.

Besides the steps mentioned, make sure your Gmail settings are correctly adjusted. Turn on the option Insert signature before quoted text in replies and remove the “–” line that precedes it.

1. Open Gmail and click on the gear icon (Settings) at the top-right corner.
2. Select See all settings.
3. Go to the General tab.
4. Scroll down to the Signature section.
5. Ensure that Insert signature before quoted text in replies and remove the “–” line that precedes it. is enabled
6. After making the necessary changes, remember to scroll down to the bottom of the page and click Save Changes.