[RamsFanSam]

Yes, you can have signatures. However, there are limitations. For instance, they have to be at or below a certain size, must be appropriate for a family site, and I believe they won't show up in posts of less than a certain length. Premium members have slightly different restrictions.

I'm not sure if the signatures show up unless you have a minimum number of posts, though.

Signatures are set up in the user CP.