A text editor is a specific software designed to write and manage your code better. It is one of the most important tools utilized by a web developer.
Code complettion allows you to write parts of your code and the completion feature will display possible coding options to use. This is an extremley helpful feature because it saves time and limits typos.
Synatx Highlighting is a feature that displays text in different colors. This makes your text easier to read for you and for others.
This feature allows you to select several different background colors along with the color of the text for your theme.
Using extension simply just allows you to add other cool features that you can use within your text editor.
A command line or terminal is an interface that allows you to enter in specific commands and recieve feedback. Imagine the command line being almost similar to your file expolorer. You are able to create folders, files, and navigate within them. All and more can be done with the command line as well.