Rated 4 out of 5 stars

I've used Signature switch for years, and know of nothing better. Most of my email is S/MIME or PGP encoded, required for sensitive material security. I usually use the latest Thunderbird release, 115.11.1 (64-bit) at this writing. I use Signature Switch under both Windows and Ubuntu Linux.

Here is a list of Pro's and Con's from my experience.
Pro:
- Multiple signatures allowed (Full for outside communication, contact only for internal communication)
- Easy to use, button is top right of a Compose window
- Allows inclusion of inline images (secure email doesn't allow links to external sites for this information)
- Generally works well!

Con:
- Forces signature to be at the bottom of the message as opposed to inserting signature inline at the cursor for replies (reason for 4 star rating, this is a problem) [solution is to copy/paste the signature where it's needed from the bottom of the message]