NeelamS
I couldn't think of a clean way to explain this in a forum post, so I just did a survey that explains everything. I am positive there are cleaner ways to do this if you know better programming, but this was the cleanest way I could think of with the least amount of programming knowledge needed. It does use some JavaScript, but very little. Be careful about changing the coding and embedded data names, otherwise this won't work properly.

I've included programming notes throughout this to help you understand what is going on, but ultimately you will have to reverse engineer the programming to fit your use-case.
Demo_-_Date_difference_calculation (1).qsf
After posting this I realized that you will need to make a small edit to the math calculation for Day.diff. Use this $e{ abs( e://Field/CD - e://Field/COV.dd ) }.

This needs to include the absolute value for the difference in date, otherwise you can get some negative numbers that won't make sense.

I misunderstood the question. It looks like the OP wanted to add a static number of days and not do a calculation based on the current date.

Attached is how to do this with 14 days as the static number.
Demo_-_Date_difference_calculation_-_constant_14_days (1).qsf

Thank you,Akdashboard !
Your file helped me out tremendously! I was able to branch this to work for two types of conditions. Appreciate your willingness to share.