IRA Individual Retirement Account. If you have earned income from working or a Net Profit from self employment you can contribute to a Traditional IRA or ROTH IRA.
IRA Contributions IRS Pub 590a.
https://www.irs.gov/pub/irs-pdf/p590a.pdf
A Traditional IRA contribution gives you a deduction now and it is taxed when you take it out. It is all taxed, including the earnings and growth.
ROTH contributions do not give you a deduction now. You pay tax on your total income now but when you take a ROTH Distribution it will come out tax free and the earnings will be tax free also.
You can usually invest your IRA in anything. IRAs are self directed accounts. You can open an IRA almost anywhere like a bank, credit union, broker or mutual fund. You can buy any investment they offer so check around to see what they have. But your money will be locked up until you retire so make sure you won't be needing it. You can take it out early but there is a 10% Early Withdrawal Penalty if you are under 59 1/2.