How can upload captures in xbox app with pc?

Thank you for your answer. I know how to upload captures from my xbox. I wanted to know, how to upload them from my PC to XBox Live.

I downloaded the XBox Console Companion App and there one can read, that uploading screenshots from PC to XBox Live is currently not possible.

Actually, with the Xbox App on a PC you can download or UPLOAD captures to your feed.

I am on my PC, using the Xbox app on my PC. All captures recorded with the Microsoft Game DVR while playing on my PC. I can see the videos in the app under captures like usual. However, when i try to upload them to Xbox Live a message appears that says
can’t upload capture, we don’t recognize this game. The problem is now happening with Forza Horizon 4 as well. I’ve found posts suggesting trying the beta Xbox app and I was able to upload a few Forza Horizon 4 captures before the problem occured on that app
as well. The beta app wouldn’t let me upload BFV clips either. I tried resetting the regular Xbox app in the app settings and that works for awhile before the issue comes back. I’ve seen posts as old as 2016 stating this issue.

The best way to keep those clips is, install the Xbox app on your laptop or pc. Then on your console go to your captures and upload them to one drive and upload them to live. Then go to the Xbox app on pc or laptop click on the captures and scroll through
what is live and download the clips to your pc or laptop in a file.

I have the same question, but what I think OP is trying to ask is, how do we take a game clip captured on PC through the Xbox Gamebar and upload it to the Xbox PC App, so that we may share it to our friends through the app?