HOW TO CHANGE FILE EXTENSION

How to change a extension of file and how?

IF YOU WANT TO CHANGE FILE EXTENSION THEN THE FIRST THING
OPEN YOUR
STEP 1:-
I WANT TO CHANGE ONE .pdf  FILE EXTENSION
FIRST  OPEN AND GO TO THAT LOCATION WHERE YOUR .pdf  FILE IS STORED

i have described in below image

you can see DIGITAL PAYMENT
but it's extension is displayed here

then RIGHT click on DIGITAL PAYMENT ---->properties--->

i have described below in image
and you can see
i have highlighted with yellow mark
extension also not displyed there
  

click ok

THEN GO TO

 CLICK ON VIEW ----->OPTION

I HAVE CIRCLE WITH RED MARK IN BELOW IMAGE

 

 AFTER CLICK ON OPTION GO TO
YOU CAN SEE THIS TYPE OF IMAGE ON YOUR SCREEN

THEN CLICK ON VIEW  ----> HIDE EXTENSIONS FOR KNOWN FILE TYPES  

UNCHECKED       file extensions for known file types 

click ok

i have unchecked you can see in below image

then again
CLICK ON PROPERTIES OF DIGITAL PAYMENT FILE

YOU CAN SEE .pdf EXTENSION WITH FILE NAME

CHANGE IT
ONLY DELETE .pdf EXTENSION
and type .rtf EXTENSION

I HAVE DONE IT
YOU CAN SEE IN BELOW IMAGE

THEN CLICK OK

CLICK YES

THEN SEE YOU FILE EXTENSION IS CHANGED