Utility Classes in MVC – ASP.NET

So I was wondering today, where would you put utility classes in an ASP.NET MVC app? By utility classes I mean classes that can be static and are just used to perform a function. Like a class to send an email that takes email address , subject, and body as arguments.
I would assume maybe creating a separate folder and namespace would be good enough, but wanted to get everyone opinions

Hiding query strings logically?

I feel uncomfortable when using query string parameters as:

Hiding query strings logically?

I feel uncomfortable when using query string parameters as:

Hiding query strings logically?

I feel uncomfortable when using query string parameters as:

Hiding query strings logically?

I feel uncomfortable when using query string parameters as:

Hiding query strings logically?

I feel uncomfortable when using query string parameters as:

Hiding query strings logically?

I feel uncomfortable when using query string parameters as:

How to prevent fat views in MVC?

I’m just curious. If I’m a lead dev in a company of a dozens of developers is there any way I can prevent a newbie developer from creating a fat view?

How to prevent fat views in MVC?

I’m just curious. If I’m a lead dev in a company of a dozens of developers is there any way I can prevent a newbie developer from creating a fat view?

How to prevent fat views in MVC?

I’m just curious. If I’m a lead dev in a company of a dozens of developers is there any way I can prevent a newbie developer from creating a fat view?