When you make a IRA contribution you can either deduct it from your tax return which will wash out the tax you paid on it originally. It will grow tax deferred. Then in the future when you take a distribution you pay tax on the distribution.
Or you can make a non deductible contribution to a Traditional IRA or to a ROTH IRA. You do not get a tax deduction for it and it grows tax deferred or tax free in a ROTH. Then in the future when you take a distribution the non deductible part will come out tax free and you only pay tax on the growth. Or not pay on the growth in a ROTH IRA account.
See IRS pub 590 A for IRA contributions
https://www.irs.gov/pub/irs-pdf/p590a.pdf
And 590 B for IRA distributions
https://www.irs.gov/pub/irs-pdf/p590b.pdf
