Open the YouTube app or go to YouTube Studio
Sign in to your YouTube account
Tap Create or the plus icon
Select Upload a video
Choose a vertical video under 60 seconds
Make sure the aspect ratio is 9:16
Add a title
Include #Shorts in the title or description if needed
Select a thumbnail if available
Choose the audience setting
Add any other details you want
Tap Next
Review the video settings
Tap Upload or Publish