First, you must have compensation from working. As long as you have compensation from working, you can contribute to an IRA. The age limits and the idea that you can't contribute after you retire were recently changed.
However, you must still follow all the normal contribution rules. The income phase out for Roth contributions starts at AGI of $138,000 depending on your filing status.
https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-ira-contribution-li...
If you want to make deductible contributions to a traditional IRA, the income limits are here.
https://www.irs.gov/retirement-plans/ira-deduction-limits
If you can't make deductible contributions, you could make nondeductible contributions and then keep track of your basis or do a backdoor conversion.
