Hi, Havalana! In order for everyone to see your screenshots, you need to upload them online using a hosting service that allows direct links to images (such as Imgur—which is free!).

Your PS4 should automatically place a watermark/copyright info on any screenshot you take in FFXIV, so you shouldn't have to worry about that (I know on my tv it's hard to see in the corner, but it's always there). I take my screenshots just using the Share button and Capture Gallery and I haven't had any hiccups with the info appearing where it should. I hope I could help!