You could zoom in with the scale function in Motion settings until the portait video fills the screen; but zooming a lot will give you fuzzy video.
You could use it ilie a PIP and put info or captions beside it.
It depends on what you want the project to look like. Can you give us some more info?
Welcome to the forum.
When you say that you "shot in portrait," are you talking about video, or stills used to produce a video?
Curt has given you some options for video, but if still, used in video, there are some other options.
I'll wait for your response, prior to offering some other suggestions, as what you have, and what you want, will dictate the way to handle the images.
Good luck, and let us know exactly what you have,
Use Motion Effect to Rotate and scale to zoom out to fit the video image into the landscape frame.
You will need to deal with the black space on each side.
There are many ways to do this. ( ask)
BTW - we are going to see more of this due to still cameras being used as Video cameras. ( I have always hated still cameras used in Portrait mode anyway but for video... thats the giddy limit for me!)
So far, I've seen mostly troublesome mounting locations as the culprit for vertical footage. However, I do agree that the potential does exist for still/vid cameras to be used inappropriately. It happens. Going back decades, my wife shot the last race that I campaigned my XKE in "portrait" mode, as she was used to her Nikons, and I had handed her my Beaulieu 16mm to shoot my last race. We got almost 400' of "vertical" footage. Now, if I telecine it, I can Rotate in PrPro, but that was not an option way back then. Maybe then, my wife can finally put it all behind her. Also, I lost the race to 3 - 6 cyl. Porches, but was within about 2 sec. of the slowest of them. Fourth place was not THAT bad, as I did beat about 20 other autos, but not having the footage was painful.
A couple of those suggestions sound like they'll work. I can't get back to this project until Friday, but I'll let y'all know if I need more help. Thanks!!
An alternative approach, without any hits in quality, is to just rotate the TV 90 degrees during playback.