To upgrade from MoeGo Lite (Free) to MoeGo Premium, there are 2 ways:
Option 1: Login from MoeGo website: www.MoeGo.pet, then go to Account -> Billing, you can chose the MoeGo plan from there.
Option 2: Login from MoeGo app, simply click on Upgrade button to chose MoeGo plan.
For MoeGo pricing, please refer to website: www.MoeGo.pet