Caused by 2 reasons:

If you extract element and use it before its completely loaded

If you extract element, change page and then come back to original page and use element

Okay Sir. Could you please suggest best way to handle it., In my script I have to enter one value in the text box and then I have to hit enter. it is givign excpetion at that time staleElementReferenceException. Could you please advice.

You can put some delay like thread.sell or explaicit wait before interaction