I've used the United mobile app and love it, but that was when I was the only one on the reservation

I've used the United mobile app and love it, but that was when I was the only one on the reservation. How does it work if I've also booked someone else on my reservation, so there are two of us to check in? I entered their FF#, should they see it on the United mobile app? I'm certain this is not rocket science, but can't figure it out and can't find the answer on the new UA site. When I look at the mobile app, I see the reservation with both of us listed...
I just wanted to follow up. I was able to check both passengers on the ticket in via the online app, but you cannot use it for the boarding pass as well. I had to either find a place to print out the boarding passes that were mailed to me, or get to the airport and "reprint" the boarding air boat tours florida pass...we'd checked in but just needed it printed.
Marjia, Cleveland is equipped for boarding passes, it's that the app did not generate them for either of us once I'd checked in. I've used the United app at other locations and ordinarily it generates the bp right away. When checking us both in, it only allowed us to receive emailed bps.
Does the app give you the option of using a different e-mail address for each passenger like the website does? If so, you each should have been able to display your boarding pass on your phones' browsers via the link in the e-mail (unless of course one pax doesn't have a smart phone).
air boat tours florida I've done that a number of times with two or three passengers on one PNR--but when checking in from the website rather than the mobile app. It gives me the option to enter a different e-mail address for each passenger, and then each of us launches our own boarding pass.
I checked in from the app for my flight yesterday and selected the e-mail option, and then launched the boarding pass from the e-mail (although I could have also launched air boat tours florida it from the app)--so no need to print. But I was traveling alone. I have a multi-passenger flight next month, so we'll give it a try then.