Why is there a right margin line in Android Studio editor window?

Issue

There is a vertical line in the middle of the file editor window in Android Studio. I'm unable to change the margin line. Below is the screenshot of the right margin line:

Where is the setting to change this line?

Solution

I guess you mean this line?

That's a ruler for the max column width.

You can change the max column width from:
File > Settings > Editor > Code Style > Right Margin (columns)

Answered By - Ahmad