Thanks so much for your prompt reply. Once I found the IRS Direct pay page, it seemed pretty straightforward to me.
The other IRS make a payment site seems to take you to a page where you have to sign in with ID.me, though when I looked into it that system seems to have had some security issues, so I'd rather not go through with ID.me's registration process / a 3rd party. Interesting that the IRS Direct pay page https://directpay.irs.gov/directpay/payment?execution=e1s1
allows one to log in / verify their id with name, address, ss # as identifying factors.
