The 3-dot menu’s “Close” does close tabs, but tabs only contain single files, so I’m not sure what you’re seeing. Could you post a screenshot or explain further?
In the following image, I’m calling the Tab the part where it says “An introduction to Local Gra…”
It is the only Tab I’ve got open in the top ribbon.
Underneath is an arrow, I’ve circled it in red.
When I click on the arrow (pointing Right) this file opens:
The file has changed within the same tab.
I can click on the left arrow to go back to the previous file, or the right arrow to open the next file (file 3 of 3 here).
Because this is the last file in this tab, there is only the option to go back using the left arrow.
If I now go to the 3 dots on the top right of the file,
I can choose Close.
and if I click on it, it closes whole the tab:
…
I am wondering if there is a way to close just one of the three files instead of the whole tab?
Those are your history arrows — they’re like your web browser’s back arrow, or a text editor’s “recent files” list. They let you reopen files that you’ve opened recently. Obsidian remembers what files you’ve opened in each tab, in the order you opened them, and those arrows navigate that list. They’re just a convenient way to reopen files — the only one that’s open in a tab is the one that’s visible. The others are already closed.
It’s probably technically possible to edit your recent files list, but I don’t know of any easy way to do it.