App recommendedations?

So about 1 month pp, I'm moving states to live with my best friend and her (then) 6yo and 4mo. Single moms unite! We were talking about getting a dry erase calender today for everybody's schedules and work and etc and I was wondering if there were any shared apps yall might know if? I'm sure there's a way to keep organized both at home and on the go. Just wondered if anybody had a good app to share ❤️