Will adding the cover letter to my resume make a difference? and what's the added value of it?

Hi Nourahn, Thank you for asking such a question! I remember this has been coverd on Bayt.com blog. Here's the link to the article. Enjoy reading :) 

http://www.bayt.com/en/career-article-422/

ITS BASICALY THE INTRO OF YOUR COMMUNICATION.

It will make a different

C.V. without cover litter = litter without postage stamp

Providing a cover letter that is personalised each time for a different company is what adds value as compared to a standard -copy-paste cover that is used everytime. 

If cover letter wants by the employer, please add with CV. If it is not required for job, do not submit cover letter. Follow what is the requirement by asking employer?