Hello,

I want to insert colon after every indentation to an existing text.
Example:

My current text is like this:
JOHN Good morning!
JACK Good morning!

And I want it to be like this (with a command) because the existing text is very long to enter them manually, one by one.

JOHN : Good morning!


JACK : Good morning!

What do I need to do to insert colon in every line after second indentation?

Thank you in advance.