You do not "file" quarterly taxes. You "pay" them. You only "file" a tax return once a year. To pay your quarterly taxes to the IRS online just go to www.irs.gov/payments and do it there. ***PRINT*** ***YOUR*** ***RECEIPT*** when done. When dealing with the IRS, if it's not in writing on a physical piece of paper, then it flat out did not occur.
If your state also taxes personal income and you need to pay your state quarterly taxes, then that is a totally separate transaction between you and your state taxing authority. Not all states have the ability to pay your state quarterly taxes online. So you'll need to check with your state's tax website to see whatever payment methods may be available to you.
