For that, start with this thread:
Also, Easel by Inventables works really well for doing signs. It has a really good preview mode to show you what it will look like. Unfortunately they’ve removed some things from the free version - multiple passes and custom bit shapes/sizes. But occasionally it’s worth the $20 for a month when I’m doing some specific projects. I think you can get a free trial month. (Have to do a couple things to get g-code to work with SM, but nothing difficult. Ask (or search) if you want to try that.)
EDIT: Just saw you mentioned Easel. It can do extruded. Just have to invert your artwork.
-S