When I get a chance, I'll be removing the off-topic tech stuff from this thread, but in the meantime...
When I first got an iPhone, I didn't intend to use it for anything other than phone calls and texting, so I didn't want to synchronize it to my Mac computers. Later, when I did want to access stuff from time to time and wanted my Safari passwords saved, I decided to synchronize it.
Not overly familiar with the iPhone, I screwed something up and, before I knew it, all of my photos on either of my Mac devices had been duplicated on my iPhone, and my iPhone was out of space. I didn't want that. I only wanted the photos that I took on the iPhone to be on the iPhone, and I certainly didn't want my computers and my iPhone to be near-duplicate images of one another. Whenever I deleted photos from my iPhone, they would automatically reappear.
My wife helped me sort that out, although it involved hours of deleting crap I didn't need from the iPhone. Now my Safari passwords are saved when I open Safari on my iPhone, so I can access the forum, Amazon, etc.
However, I don't fully understand it, so I won't be able to help beyond saying that it can be done.
Apple support could probably help. Other options might be the official
Apple Support Community, which I haven't used myself, or the
MacRumors forum, which I have used. If you search, you might find that someone else has already asked the question. Otherwise, someone might get snarky, since there are always people who hang around only to insult people who don't already have all the answers, but someone else will probably come up with a solution.