There are a million different ways to configure Apache and what you have stated sounds like a possible solution for multiple sites, but not what I would personally use.
I'm a little confused as to why you might use Linux Mint, a desktop Linux distribution for a web server, but I assume you know what you are doing. Maybe you want a test environment for development work.
<VirtualHost> directive is used for hosting for multiple sites on the same server and that is about it. The contents of each
<VirtualHost> grouping contains the configuration options that are different from the main host and main config.
But then you ask: "Is it mandatory to use
VirtualHost in Linux Mint?" and the short answer is no, unless you want to host more than one site.
I think the real question is something more like:
I am trying to set up a development environment with Apache on a Linux
Mint desktop and I'm a little unsure how to configure it correctly.
This is what I have currently and it is not working... list of
what you tried and what went wrong
At the moment, your question is not very clear. Maybe edit your question to include a little more detail on what you are wanting to do with Apache.