It’s an iOS feature which means you can hold the spacebar to turn the keyboard into a “trackpad” and move cursor or select text. Here is the website showing how to use it: Type with the onscreen keyboard on iPhone - Apple Support
And here is a screen recording in most other Apps such as Apple Notes, you can see the page scrolling up and down when moving the cursor:
However, in Obsidian, the page doesn’t move up. Instead, the cursor jumped to Title:
