1) First of all, you need to open Launchpad and find the app from the list you want to delete.
2) Now drag that app to trash to delete it.
3) Now open up the Finder in Mac.
4) Now in the search box enter the app name you just deleted and hit enter.
5) Make sure at top bar you have selected the "This Mac" line.
6) Select all files and move them to trash.
7) And at last, empty the trash to completely delete the app from your Mac.
