That's such a generalized question, it's kind of hard to give a meaningful answer. Some seed-grown fruit trees can produce fruit withing a very few years (maybe some even within a couple of years) and some can take decades. Can you at least narrow down the type of tree(s) you have in mind?

Oh yeah, I forgot to say...

Many types of fruit trees are almost always propagated vegetatively (cuttings, grafted trees, etc). Most apples for instance are unlikely to produce good fruit when grown from seed. Are you only interested in seed grown trees or are you just trying to find out how long it will take for you to grow your own fruit?