Upwork, accepts various payment methods including credit card, debit card, PayPal, and bank transfer. However, as far as I know, Upwork does not accept payments by check.
Regarding carrying a credit on your account, you can fund your Upwork account with a certain amount of money to cover future projects, but you cannot carry a credit balance on your account. Upwork charges fees on a per-project basis, and the funds for each project are deducted from your account balance at the time the project is funded.
If you wish to fund your Upwork account, you can do so by logging in to your account, clicking on your name in the upper right-hand corner, selecting "Settings," and then selecting "Billing Methods." From there, you can add a payment method and fund your account.
If you have any further questions or concerns, I recommend reaching out to Upwork customer support for assistance. They will be able to provide you with more information on their payment policies and options
