There are two types of subscriptions - those made directly on platform.move.ai and legacy plans purchased through the iOS App Store
If you are a Move subscriber:
Head to platform.move.ai
On the left hand side, open the Billing tab.
Make any desired changes here via your Stripe account.
Legacy Move One subscriptions can be managed in the App Store, as Apple manages the billing system. Head to the Subscriptions section in the App Store to locate your Move One subscription.