Throughout Google’s help documentation they will tell you to select a payment method. There is a caveat though, which will prevent you from doing so and that is not widely known or understood.

You can find information on how to set up your desired form of payment in AdSense by visiting the following page:
Set up your form of payment for AdSense

Caveat: If you’ve just set up a new Google AdSense account, you can’t add a payment method in Google Adsense until your account reaches the payment threshold ($100 minimum). This is noted at the top of the page linked above (although it could definitely be phrased more clearly and be called out more prominently, especially since this is for users who are new to AdSense):

When your earnings reach the payment method selection threshold, you can select your form of payment.