When I update software on ubuntu 18.04 there s an option to upgrade to 20.04 what will happen?
 

If I click on the upgrade option will it upgrade from 18.04 to 20.04 without changing any of the programs or files that I have setup on 18.04?

All your Ubuntu programs will be updated to the versions in the latest LTS issue. Your own files will be preserved, as will any configuration you've done. Read all about it here;
How to upgrade safely

Thank you for your help. I feel a lot better about upgrading now. Previously I tried to upgrade with dvds I got from ebay but discovered they were useless.