You can set a signature for every post you will make in this site. In order to achieve this, you have to select the Edit Account
menu item of the User Menu
. This will bring you to a page where you can edit your profile. If you scroll down a bit, you'll see a row called Signature
User Profile : Signature
This is where you should write the text you'd like as your signature.
Also, if you'd like your signature to be attached to every
post you make on this site, make sure to check the Always attach my signature
Don't forget to hit the Save Changes
button at the end of the page.