At long last, Obsidian has a Share Sheet extension. However, it is extremely limited. For instance, when you share a webpage, it only transfers the URL.
Save to Obsidian is an iOS shortcut that saves any Share Sheet input into Obsidian.
Features
• Saves web pages, not just URLs
• Optionally appends input to existing note (especially useful for images!)
• Embeds YouTube videos
• Handles rich text
Download it and give it a try!