When a person goes to apply for a mortgage, the credit card does not have to be paid off, and whether the credit card is paid off has little effect on the mortgage. As long as you have good personal credit, meet the loan conditions of the bank and have sufficient assets and financial resources to repay the principal and interest of the loan on schedule. Then the bank won't care too much about whether your credit card has been paid off.
But if your credit card is overdue, it will have a certain impact on the handling of mortgage. Because the overdue credit card is reported to the central bank, and you apply for a mortgage, the bank will definitely check the borrower's credit. Therefore, if the bank finds that your personal credit report has bad credit records such as overdue, it is likely to reject your loan application.
Of course, if you are really worried, you can also choose to pay off your credit card first and then apply for a mortgage in the bank.