Deductible IRA Contributions for 2021

I am retired with no Earned Income, my spouse is self employed with a SEP.  The TT Home & Business wizard is suggesting that we both can contribute to an IRA and reduce the amount of tax owed by lowering our net taxable income.  My understanding is that you must have earned income to contribute to an IRA.  Am I allowed to contribute to an IRA because we file as Married Filing Jointly and together we have earned income from her business?  This article doesn't fully explain in a way that I can understand.  https://turbotax.intuit.com/tax-tips/investments-and-taxes/deductions-allowed-for-contributions-to-a...