Environments

What's a $\LaTeX$ environment?

An environment is a predefined context within a document that applies specific formatting, structure, or functionality to the enclosed content.

We've already seen these contexts for document, itemize, enumerate, etc...

So the syntax has already been explained:

\begin{environmentname}
    ...
    your stuff
    ...
\end{environmentname}

Popular environments

What are the environments (apart from document) that are a "must include" for writing in $\LaTeX$?

equation (or align/gather)

It's used for mathematical expressions, almost like the 4 $ signs. It's included in the amsmath package.

Formatting in this environment can add different features: for example, it automatically enumerates the equations, making them easier to reference later in the text, and offers integrated captions/label support.

The four dollars syntax, to be fair, it's considered deprecated (but a lot of people still use it _{^{(myself included)}})

minipage

It's used to create text boxes or side-by-side content.

It's just a small page inside your main page (quite literally).

Easier done than said!

\begin{minipage}[t]{0.5\textwidth}
  \lipsum[1-2]
\end{minipage}%
\begin{minipage}[t]{0.5\textwidth}
  \centering
  \includegraphics[width=\textwidth]{example-image-a}
  \caption{Example figure}
  \label{fig:example}
\end{minipage}

...and many more!

• tabular: to create tables
• figure/table: for adding and formatting figures side by side
• listings: to write fancy code in your document
• multicols: to display text in different columns
• center: quite self explanatory

Note that a lot of environments are package-provided.

Custom environments

If you get good enough (or even if you don't) you can create your custom environment!