Also, is there any penalty for not paying that amount sooner? And what is the nature of that penalty -- just additional money owed? Not something that would affect my credit score, right?
Your 2023 Form 1040 will show the amount you owe on line 37 of the tax form. Any late filing penalties and/or interest will be calculated by the IRS and the IRS will bill you for those amounts. TT does not calculate late filing penalties or interest.
If you have federal tax due you can pay by mailing your payment with the 1040V voucher, (which has the address printed on it, having the payment taken out of a designated bank account, or you can pay directly on the IRS website.
https://ttlc.intuit.com/community/tax-payments/help/how-can-i-pay-my-federal-taxes/00/26212
To apply for a payment plan with the IRS
Apply Online for a Payment Plan
You must pay your state tax due using the state’s preferred method of receiving payment. For most states that will be by making a payment to the state’s own tax website, or by mailing a check or money order.
WHAT IF I CANNOT PAY MY TAX DUE?
Your tax due will be on the 1040 line 37. When did you mail it? Did you use the Online version LAST year and just print it out now to mail or did you use the Desktop installed program? If you used Online then print out a copy for yourself (which you should do anyway). Yes the 2023 tax due payment was due April 15, 2024 so the IRS might send you a bill for a penalty and interest.
How to Access prior year online returns
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/00/27010
If you can't get the side menus to open up to access the prior year..... You need to start entering some basic Personal Info in 2024 for the side menu to open up. Just continue a little ways into 2024. I had to go though about 12 screens.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as certified mail so you will know the IRS/state received the return.
Federal and state returns must be in separate envelopes and they are mailed to different addresses. Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.