Is there an easy way to remove some of the built-in apps on macOS Mojave?
Go to the Applications folder in the Finder tool;
right-click on the unwanted application;
click "Move to trash", and enter the password if requested by the system;
then empty the trash.


Note the following exceptions:


In case an unwanted application is in the Utilities subfolder, the first step should be to navigate into that subfolder.
There are some applications such as Safari and Siri for which there is no "Move to trash" option.


Each of these steps should be well documented. I would be happy to add some more pointers upon request.