Sure, at our age, we mostly just want to stay fit enough to enjoy a ride. Even that takes some training. Cycling training is in many ways like training for any sport or recreational activity. It takes some time, proper nutrition, and structure to reach a level of comfort during the activity.
Let me assure you, you can just jump on your bike and head out. If you want the exhilaration and motivation that comes with improvement and achievement, you will want to get on the bike several times a week.
Cycling training experiences, training plans, and, yes, training apps are all covered here.