You can purchase an Uber One membership directly in the app.
In the Uber Eats app:
Subscriptions renew automatically.
You can cancel your membership at any time in the Uber One section of the Uber app by selecting Manage Membership, then End Membership. If you cancel less than 24 hours before your next renewal day, you may see a charge that will be automatically refunded. Except where prohibited by law, your subscription charge is non-refundable once your billing cycle begins.
Note: You must have the latest version of the app to purchase.