You can't include expenses you paid in 2020 (or earlier) on this year’s 2021 tax return. If you forgot to include them, you'll need to amend your prior-year return to claim those expenses.
Likewise, if you paid tuition in 2021 for the 2022 school year and the classes begin in the first three months of 2022, you’ll include them on your 2021 tax return.
