How do I turn off auto-renew for my subscription?

Android

Subscriptions can be canceled only through Google Play. 

1. Go to your Google Play application. 

2. On your profile click on Payments and subscriptions.

3. Here you can select the subscription that you wish to cancel. Follow the instructions. 

Your subscription will not get canceled by uninstalling the app!

For the most updated information please visit: https://support.google.com/googleplay/answer/7018481

Apple

1. Open the Settings app.

2. Tap your name.

3. Tap Subscriptions.

4. Tap the subscription.

5. Tap Cancel Subscription. You might need to scroll down to find the Cancel Subscription button. If there is no Cancel button or you see an expiration message in red text, the subscription is already canceled.

Source: https://support.apple.com/en-us/HT202039

Source: https://support.apple.com/en-us/HT202039