Per the IRS Instructions for Form 8880:
Who Can Take This Credit
You may be able to take this credit if you, or your spouse if filing jointly, made (a) contributions (other than rollover contributions) to a traditional or Roth IRA; (b) elective deferrals to a 401(k), 403(b), governmental 457(b), SEP, or SIMPLE plan; (c) voluntary employee contributions to a qualified retirement plan, as defined in section 4974(c) (including the federal Thrift Savings Plan); (d) contributions to a 501(c)(18)(D) plan; or (e) contributions to an ABLE account by the designated beneficiary, as defined in section 529A.
However, you can't take the credit if either of the following applies:
CAUTION! You’ll need to refigure the amount on Form 1040 or 1040-SR, line 8b, if you’re filing Form 2555 or Form 4563 or you’re excluding income from Puerto Rico. See Pub. 590-A at www.irs.gov/Pub590A for details.
You were a student if during any part of 5 calendar months of 2019 you:
A school includes technical, trade, and mechanical schools. It does not include on-the-job training courses, correspondence schools, or schools offering courses only through the Internet.
The contributions must be reduced by the amount of distributions you, and your spouse if filing jointly, received during the testing period from any IRA, plan, or annuity included under eligible contributions. Refer to IRS Publication 590-A, page 47, for additional information.
Per the instructions for Form 8880, the credit percentage is 50%, 20%, or 10% of the eligible contributions, depending on your adjusted gross income.
For the 50% rate:
For the 20% rate:
For the 10% rate:
The credit is a nonrefundable credit (meaning it is limited by your tax liability), and may be reduced by other credits.