Are you unable to insert the tab character in VS code? Does the tab key not work as expected?
Does pressing tab instead cycle you through selecting various items and buttons in the application?
If this is the case, it means you have accidentally toggled on a mode called Tab Key Moves Focus. You can toggle this mode back off by pressing ctrl-m.
After toggling this mode back off, you will be able to use the tab key again normally to insert tab characters.