document upload from iPhone to iCloud drive

Any that's supported but let me elaborate. On pc/mac is easy. You open your iCloud and either drag or copy/paste. On iPhone, you open your iCloud app and you can view or download the document ... but I don't see any option as to upload. So, let's say I have a pdf document on my iPhone that I received via email. I can upload it to apps such as Dropbox, I can upload it and e-mail it to someone else, I can text it etc, etc ... but how to upload (save) a document (let's say pdf) to iCloud from iPhone doesn't seem to be possible ... unless I am missing something.

Well ... while I appreciate the time you took to answer my question, this really doesn't answer it. I wasn't looking for a different solution, I know how to do all this ... and yes, you are correct, there are ways to do it but it requires additional steps and that's what I was trying to avoid. I was looking to find out if it can be done directly ... just one step e.g. save email attachments to iCloud from iPhone. I guess the answer is no. Thanks anyway.