I'm a college undergraduate filling out a tax return along with a 1098-T. I have a few scholarships and stipends, what do I put for undergraduate tuition paid?

If you are a dependent, the person that claims you reports the expenses if that gets them a credit. It there is taxable income (more scholarship than expense) the student claims the income. 

If you are not a dependent, you report what you paid for tuition in 2021. That is usually reported in Box 1 on your 1098-T, but it is up to you to verify the amount using your receipts and student account statements. 

In TurboTax you would enter the 1098-T. 

Scholarships are also listed on the 1098-T and may go against the tuition, other expenses not on the 1098-T such as books and supplies, or may end up being taxable income that you need to claim. 

Stipends are reported and entered by using the form it was reported on, such as a 1099-MISC

Q. What do I put for undergraduate tuition paid?

A. You don't usually enter anything; that amount is already in box 1 of the 1098-T.  You may need to adjust the amount in box 5.  The TurboTax (TT) interview will ask if you had any scholarships not reported in box 5. Enter there.

You include all  tuition paid, regardless of the source of funds, scholarships, stipend, loans, out of pocket.  If the box 1 amount is not correct, In the 1098-T screen, click on the link "What if this is not what I paid the school" underneath box 1. You will then be able to enter the actual amounts paid.