How to get split screen on iPhone XS

neetbhati wrote:

How can I view a split screen or wideout screen on rotating the screen?

As welafever said, this is not possible.

Switch apps on your iPhone, iPad, or iPod touch - Apple Support

neetbhati wrote:

For example while changing the wallpaper how can I see side by side how it looks?

This is part of the Settings > Wallpaper view.

I haven't had an opportunity to try this yet, but this might help you:

Enable Multi Window Mode On iPhone Xs, iPhone Xs Max and iPhone Xr

The first thing is to activate the Multi Window feature in the Settings menu of your device by following the instruction below

1. Power on your Apple smartphone
2. Locate the Settings app and click on it
3. Click on the Display & Brightness option
4. Select the ‘View’ option located under the ‘Display Zoom’ menu
5. Click on Zoomed
6. Select Set
7. Click on “Use Zoomed”

When you are done following the steps above, you will be able to use the Multi Window Mode on your iPhone Xs, iPhone Xs Max and iPhone Xr.

I do not think that is possible.

I will have to watch the video.