First, search the help docs and this forum. Maybe your question has been answered! The debugging steps can help, too. Still stuck? Delete this line and proceed.
What I’m trying to do
I find the mobile app very frustrating for any tasks beyond browsing my existing notes. Take importing a file, for example. The Internet recommends using drag and drop, which is not really possible on the mobile app. Or maybe the importer plug-in. I installed it, but now what? I have no idea how to use it since no new menu item appears despite it being enabled.
Things I have tried
Read the docs, read the github, installed and enabled the plug-in, poked around and found no obvious menu item to use it.
To be clear, I know perfectly well how to use a file manager to move a file from say Downloads into my vault. But how clumsy is that? Use a separate app to import a file? Come on.
Then you understand how to import your files. I would guess that Obsidian hasn’t prioritized an in-app feature for this because import is typically something a user does only once.
Another option on mobile that isn’t mentioned on the “import Markdown” page is to select the files and use the share menu, but that still involves the file manager.
You say you read the docs but you also say you looked for an interface not described by the docs, so here is a link to the Importer docs in case that’s useful (but they won’t remove the need for a file manager). Importer - Obsidian Help
You could check Feature requests to see if there’s one for an in-app import interface and comment on it, or post one if none exists yet.
If you want to import images, check out your toolbar under settings.
To import supported files, like audio or video, PDF, open your file browser, navigate to your file and move it into your vault. Try to download another file browser if the default one is complicated or poor.
Ideally, there should be a 3rd way, through Obsidian’s widgets. Right now, I can’t see any import widget, however.
for tinkerer, you can download apps to build your own (import) workflows, eg. Automator on android. Apple mobile devices have an app called workflows if I remember well.
On iOS when I am in a note and the keyboard comes up, there’s a toolbar above it and by default (at least for me) there is a paper clip icon, tape that and you’ll be able to select any file you want to attach to the note.
If you are trying to import a file as a new note, then the importer plugin will work but it’s not the same as on desktop. When you are in any tab, at the bottom of the screen there’s a toolbar and an icon with three horizontal lines. Tap on that and at the bottom of that menu there’s “Open Importer”.
The file types it can import is very limited and you’ll have to use file explorer to manually copy and paste into the vault folder you want the file in. In this aspect, it is exactly the same on desktop except for the ability to drag and drop. Even then there isa limit to the types of files Obsidian supports by default.
There are some plugins that you could install for added specific file types:
Better File Link – easier way to add external file links that Obsidian supports
Those are all I could find in my cursory search. Hope this helps explain a little better the process of importing files. It might help if you tell us what type of file you’re trying to import and whether it’s on Android or iOS as well.