Are you in the correct forum? This is for Sculptris.If thats what you are using I apologise. But… all a texture map is , is the surface of an object that has been flattened out.Imagine peeling an orange in one piece and then flattening it out.
In Sculptris this is done automatically when you click on the paint "button " after you have finished sculpting…but…it does not “peel” your object in one piece, it sought of breaks it up into lots of little pieces! But you can still save this “texture map” and use it in other 3d software, but it is difficult to use ( adjust,re paint) in a paint program. More advanced software can unwrap you objects a lot more neatly.Try Googling “texture map” for more info.