Video downloads from icloud converting to pdfs in One Drive

When I download videos from icloud they are downloaded as videos but when I move to my One Drive folder they convert...I saw someone somewhere say to use the properties button but the options don't seem to allow me to just keep the files as MP4s as they originally are... (When I download google photos videos they are in heic files and I wish there were a cure for that but maybe it's with Google that I need to change something with. 

Thanks for any assistance!