Any good app on creating comic? (Patreon)

so because I got a full time job, I am super exhausted by the time i get home and sometimes i cant even hold a pen. I go to bed everyday missing making comic, so im quitting my job in 5 months. but right now, i gotta find a way to make comic during my 4 hours of commute to work. I'm planning to get an ipad and make rough pages on it, then get home and clean them on computer. anyone know a good app on istore that lets you draw as well as Sai tool or photoshop?