Overleaf is a on-line LaTeX editing tool that allows you to create LaTeX documents directly in your web browser.
There are 3 columns
In general, LaTeX documents (.tex file) have 4 distinct parts
Packages are add-on features for LaTeX. Dozens of these are pre-installed with LaTeX and can be used in your documents immediately.
A package is a file or collection of files containing extra LaTeX commands and programming which add new styling features or modify those already existing.
Loads the package into LaTeX:
\usepackage{ }
Example packages for Maths & equations:
\usepackage{apacite}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{amsfonts}
Environments are used to format blocks of text in LaTeX documents.
Simple examples of environments:
\begin{center}
This text will be centred since it is inside a special
environment. Environments provide a efficient way of modifying
blocks of text within your document.
\end{center}
\begin{equation} x+y=67 \end{equation}