It's all combined together on your tax return. You enter your self employment business on Schedule C. You pay self employment tax on that.
You pay Self Employment tax (Scheduled SE) on a Net Profit of $400 or more on Schedule C. You pay 15.3% SE tax on 92.35% of your Net Profit (If it is greater than $400). The 15.3% self employed SE Tax is to pay both the employer part and employee part of Social Security and Medicare. So you get social security credit for it when you retire.
The SE tax will be included in your tax due or reduce your refund. It is on the 1040 Schedule 2 line 4 which goes to 1040 line 23. The SE tax is in addition to your regular income tax on the net profit. You do get to take off the 50% ER portion of the SE tax as an adjustment on 1040 Schedule 1 line 14 which flows to 1040 line 10a.
Then you enter your estimated payments. Which covers and reduces the tax due on your return.
To enter Federal or State Estimated Taxes Paid, including a state estimated payment made in January for the prior year, go to
Federal on left or at top (Personal for Home & Business)
Deductions and Credits at top
Then scroll way down to Estimates and Other Taxes Paid
Estimated Taxes - click the start button
For 2021 Federal Estimated payments should be on 1040 line 26.
