If you filed a joint return in 2018, then you both use the same total 2018 AGI.  You do not divide or otherwise allocate it.  Each of you would enter that figure to verify your efiling.

Hi. Thanks for the reply. I didn’t divide anything. I  entered our AGI - we only have one since we’re filing jointly. The rejection notice said I had entered Jean’s - my wife - AGI incorrectly. Why would they think Jean would have a seperate AGI? Isn’t that strange?

You entered the same AGI for her as for you?  Sorry to ask but did she pass away in 2019?

Hi. She passed away just last month. 
The instructions to efile required last year’s AGI. We only have one AGI, which is what I entered. They didn’t ask for Jean’s AGI. We always file jointly so that wouldn’t make sense. I entered the AGI from row 7 on form 1040, as always. I kind of think their rejection is an error!

OK. That makes sense. It didn’t occur to me that since she didn’t die in 2019 that it would have any influence filing 2019.

thanks so much for your help! I appreciate it.