How do I move a file I have downloaded onto my phone to iCloud ? I can download files from iCloud onto my phone but how do I do the reverse?

I have a lot of files on my phone in the “downloaded “ section of the files app . I want to keep those files but I want to clear up the space they are taking on my iPhone , how to I “offload “ or “upload them “ to iCloud so they are not eating up space ? I do t see any option and if I try to delete a file , it says it will be deleted from everything.