No. The full amount will not be available to you upfront. When you enroll in the CDHP and enter your HSA annual contribution amount, it is evenly divided and taken out of each of your paychecks throughout the year and sent to PayFlex each payday. You may only spend the funds that have been added to your HSA. Alternatively, you may pay for an expense with your own funds, then later reimburse yourself with funds from your HSA after your HSA has enough funds in it.