Can't find folder's Video When to upload in Youtube

Dear Community,

I capture video with my iPhone 11. I edit and rendered those file in iMovie and saved that video file in my iPhone folder. But when I try to upload that file from youtube app I can't see that video. all my capture video show there but not that rendered file although that file is exists in my iPhone. My all access is given to youtube app. So how can i see all my rendered video when i click upload video in youtube app? Please help.