Contributing to a traditional IRA in 2020 for credit in 2019.

Here's the situation. I am retired and my wife is about to retire probably in August of 2020. We have some extra funds I want to contribute to a traditional IRA in 2020 which will give garner a refund on our joint 2019 taxes.  My wife is covered by a 401k plan at work and also has two traditional IRA's while I have no  IRA's of any kind.  According to the IRA Calculator tool it appears I can't contribute any funds to my wife's IRA's .  I can only contribute to an IRA which I would have to establish.   I would have liked to put the funds in one of my wife's IRAs but that doesn't seem possible. Is this correct, do I have to open up a traditional IRA for myself and then add funds to this one?