I'm very new to dnd, and even newer to this site. This will be my first campaign, and it's going to be totally online. I'm not the dm, so I can't edit the sheets of the other players, but I can only see the character sheet of one of them. For one PC I can see their name, level, class, etc, and under it there's "View user profile" and "View", the latter bringing me to their character sheet. But the other two pc's only have "view user profile." It's not an issue of incomplete character sheet, since one of them was able to generate it and sent it to me as a pdf. So, what's the deal?

Perhaps they have them set to private? I'm not sure how that works with them adding the characters to a campaign, but it's a possibility.

Yes, it seems they have set their sheets to private view. Only they and the DM will be able to see their sheets.