4 month old feedings

Kari
So.. At 4 months they start eating jars of baby food, correct? So do they still get a bottle 3-4 hours or does it kinda turn into an on demand thing or what? 
I'm a new mom and my son will be 4 months on August 17th. I plan on asking his doctor this question but I just want to see other moms opinions and what they do. 
I know every mom and child is different. I just want a heads up.