I would like to put a electric fire on marble am I able to put screws into marble

Yes, marble is a soft stone and easily drilled with a masonry bit. Drill and insert plastic anchors and screws. Since you will probably be using small anchors and not that many, you could probably use glass and tile bits to drill holes. They are cheap but don't last long.

You should be able to.. is the marble on the floor or wall? Is it installed?
Do you have any experience with a drill?

I am able to use drill, marble is on wall but I was a bit scared of trying to drill into it in case it broke, but now that I know that I am able to I'm OK, thanks