How to use video stabilization on iPhone 11Pro Max

Hello UnDavid,

Thanks for asking the Apple Support Communities about video stabilization.

You are asking about built-in features and don't need to do anything special within settings: iPhone 11 Pro Max - Technical Specifications - Apple Support

"Video Recording 

• 4K video recording at 24 fps, 30 fps, or 60 fps
• 1080p HD video recording at 30 fps or 60 fps
• 720p HD video recording at 30 fps
• Extended dynamic range for video up to 60 fps
• Optical image stabilization for video (Wide and Telephoto)
• 2x optical zoom in, 2x optical zoom out; digital zoom up to 6x
• Audio zoom
• Brighter True Tone flash
• QuıckTake video with subject tracking
• Slo‑mo video support for 1080p at 120 fps or 240 fps
• Time‑lapse video with stabilization
• Cinematic video stabilization (4K, 1080p, and 720p)
• Continuous autofocus video
• Take 8MP still photos while recording 4K video
• Playback zoom
• Video formats recorded: HEVC and H.264
• Stereo recording"

For info about recording, please check here: Record HD or 4K video with your iPhone or iPad - Apple Support

Cheers.