How do you edit your signature in lotus notes version 8.5?
I'm using a Mac, if that has any effect.
From the inbox view, assuming you are on the full client and not the basic client, you click more-->preferences-->[mail]-->[signature]. The options for enabling the signature are pretty straight forward.
If you are on the basic client, I believe the options are the same as 7 and previous versions where you click Tools-->Preferences.
You can also use Crossware software, you can add an email signature and or disclaimer to every transferred Lotus Notes email, with a professional layout.
Here is a link for how to create a signature that holds HTML content, but one can use the same idea to make a non-html signature.