Redeem Credits
Log into your account and visit the Account page. Under the My Money section, there is an option to redeem credits for cash. Click Get Paid.
Note
There is a 30-day hold placed on all users from the time the money was earned (i.e., starting at the moment someone bought an item) before cash can be withdrawn. This is an intentional limitation.
On the resulting page, assuming the 30-day hold has passed, you can cash out your available balance to your PayPal account.
Transfer Earnings to a Partner Account
Royalty recipients who also happen to have a publishing partner account linked to their customer account can alternatively use the checkbox under the Affiliate Credit section of the Account page to have their royalty balance (or their affiliate credit balance) transferred automatically into their publishing partner account earnings balance at the end of the month.
This transfer occurs just before end-of-month automatic PayPal payments from customer accounts, so it allows autopaid royalties (plus affiliate credits earned in the affiliate program, if any) to be combined with publishing partner earnings into a single, automatic monthly payment.