I have a 1099int letter from the irs but dont know where to put it

If you received a form1099-INT from IRS, when entering the 1099-INT use the IRS as the Payer name and the amount received in box 1.

To report interest income received -

Click on Federal Taxes (Personal using Home & Business)
Click on Wages and Income (Personal Income using Home & Business)
Click on I'll choose what I work on
Under Interest and Dividends
On Interest on 1099-INT, click on the start or update button

Or enter interest income in the Search box locate in the upper right of the program screen. Click on Jump to interest income

On the screen Did you receive any interest income? Click on Yes

On the next screen click on Continue

On the screen Let's import your tax info Click on Change how I enter my form

On the screen How do you want to add your 1099‑INT? Click on Type it in myself