How to load another file's content to the current file in Vim?

Solution 1:

at the VIM command prompt:

:read new_file

or for short:

:r new_file

This will insert the contents of new_file under where the cursor is. For instance if this is the contents of new_file:

I do not like green eggs and ham 
I do not like you sam I am

And this is the text you're editing:

I meant what I said and I said what I meant
An elephant's faithful one hundred percent.

And your cursor is on the first line and you type:

:read new_file              

Then your buffer will be:

I meant what I said and I said what I meant
I do not like green eggs and ham 
I do not like you sam I am
An elephant's faithful one hundred percent.