Payments are calculated based on the outstanding line balance each month. You can always pay off your outstanding balance at any time.
Because HELOCs are lines of credit, regular payment amounts are not usually fixed.
During the draw period (10 years6,7), you will be required to make recurring payments with a minimum payment determined by the lender. During the repayment period, you will be making recurring minimum payments determined by the lender. Your lender will calculate the recurring minimum payment amount using a method that will be described in your loan agreement.