Looking for good work out tips

Me and my boyfriend are trying to find ways to work out with our busy schedules. We are pretty active at our jobs but we seem to have gained some fat on our bellies. I have been trying yoga to tone and tighten and do daily walks but with nothing to show.

He has been biking everyday to and from work and had gain plenty of leg muscles but it hasn’t affected his stomach.

Any tips on how to get rid of stomach fat??