On iPadOS with a keyboard attached, I have access to a spotlight search, a bit like MacOS.
When I search for a note via Spotlight, it tells me that .md document is an IAWriter document inspite of the fact I’ve never had that installed on my iPad. When I attempt to open the file I get a plain vanilla white text viewer.
Oddly if I open the same note from Files it goes to Obsidian.
FWIW My vault is stored in iCloud.
How to do I get Spotlight on iPadOS to realize that markdown files in the vault belong to Obsidian?
Weird, I do have iA Writer installed and my Spotlight results don’t mention it. I think I get the same results as you —within the Files section of results, tapping on the file opens it in Preview. Tapping the “Search in App” link next to the Files heading opens that section’s results in a Files view, and tapping the file there opens it in Obsidian.