In what format, codec, and what else do they have, should there be a video to embed on the site?

Question

HTML

Hello everyone, the client sent a video in a .mov file and asks to insert it on the site.
I used to only copy videos already posted somewhere on the web, there were no problems with them.
And here is some trouble. Converted to .mp4 - plays only on desktops. I read that there is some kind of h264 codec - I recoded it into it - it plays on androids, on desktops in terrible quality, does not work on ios.
Is there any service to upload a video there and get a set of files at the output that will be played everywhere?
And another question - what, the video tag really does not support different paths for different client resolutions? Well, how's the picture?

Answer 1

Well, a ghost with the nickname Developer appeared and deleted his answer, which was the solution.
Everything is easier than ever - upload to YouTube and download back.
Upd: The client's video plays on 1 out of 3 phones. I play everywhere. All Android phones. How can this be???