Can you use latex paint for a wood fence?

What do you mean? Yes, paint on wood trim is typically latex these days. Some older homes may still have alkyd (oil), though. To find out for sure, put a little nail polish remover on a cotton swab and rub it on the paint in an inconspicuous location. It it gets soft and starts to come off, it's latex. Either way, sand it lightly and recoat with the same type of paint and you're good. If you're asking about bare wood, DON'T USE LATEX! The water will swell the grain of the wood. Use an oil primer that is made to take latex topcoats.