Online payment methods are preferred. The IRS mail is backed up due to COVID-19. Additionally, online payments will give you a receipt that you can show the IRS if they should "lose" your payment.
Paying Your Taxes
Certified mail
If you mail anything to the IRS, send it by certified mail with return receipt so you have proof that your payment was received. You can also stop by your local IRS office and make a noncash payment in person without an appointment.
Don't forget your state
If you live in a state with an income tax, you may wish to may state estimated tax payments. TurboTax has links to all state tax websites at How do I track my state refund?
