You can contribute to your HSA in three different ways.
You can contribute pre-tax dollars from your paycheck
To make or change your contributions from payroll you will need to contact your HR team and ask request the change. They will be able to make the adjustment for you.
One advantage of contributing during payroll over a contribution made from your bank account is is that payroll contributions made will not be subject to Social Security and FICA taxes.
You can contribute directly from your bank account
You can contribute to your HSA through a linked bank account at any point in the year. At the end of the year, you will receive Tax Form 8889 where you can claim post-tax contributions as tax deductible.
Your employers can contribute to your HSA
Employers may contribute a set amount to your HSA or offer contribution matching. However, employers are not required to offer any contribution to your HSA.
To find out if you could receive a contribution from your employer contact your HR team to discuss your company's HSA program.
Keep in mind that you are subject to a yearly total contribution limit based on your total contributions, no matter the source.