Quick question, please help! Is having control over files in cpanel the same as shell access?

I had been using templates for my sites while learning how to design websites. Well, of course when I realized how I was limiting myself I immediately built my first website from scratch. My mother (a website designer who gave me great books and software to learn from) recommended I use Omnis for my hosting and of course I did.

With Omnis I was able to look into my files directly in the cpanel files manger area and make any edits to the html and even view the changes before I saved them. I have not used any other host for running a non-template site so I have nothing to compare this (what I thought was an excellent) experience with.

My question is: Is this feature called "Shell Acess"? I was so used to doing this at no extra charge (Omnis does not upsell any of the features, they are available to everyone for the same price) and therefore have no clue what are considered industry standards. I ask this because I have run across a term which is new to me (shell access) which other hosts are charging extra for.

I am basically trying to decide if I am going to stay with Omnis or go to another hosting company (for economical purposes). I don't want to get less than what I am accustomed to but I also don't want to pay extra for features that are considered standard.

Any clarification would be welcome.

Thank you in advance.