How to apply credits towards your subscription bill
Did you purchase credits for international calling and messaging and wish to apply that amount towards your monthly subscription instead? You can!
Click "Settings" from the left-hand menu of the web or desktop app.
Under "Workspace", click on "Plan & billing".
Scroll down to the credits section and click "Use Towards Subscription".
That's it! Credits will be applied towards the next billing period of your OpenPhone plan. Keep in mind your full credit balance will go towards your subscription so you won't be able to specify an amount.