Does cracking my iPhone screen void its warranty?

I don't have insurance.

I need my lock button fixed. Will Apple fix it if my back screen is cracked?

When I cracked my iPhone screen I didn't have insurance on it so it was very costly. Apple replaced my phone because they do not replace the front glass. (but they do replace the back glass). After I got it fixed I bought insurance on it just incase it happened again which it did so I recommend getting the insurance because the repairs are much cheaper.