A large portion of the Monero community communicates through IRC channels.
Matrix offers the best of all worlds for many people. It's free, open source, federated, nicely designed, and even communicates with IRC channels and users.
This guide will help you connect to Matrix using Element. Element is the most common application for Matrix chat servers. You may use another preferred Matrix application if you prefer, but that is outside the scope of this guide.
Element is free and open-source. It's available on the web, on desktop, and on mobile.
In this guide, we will walk through using Matrix in a web browser with Element. Please refer to the other guides for Android and Apple iOS:
First, go to https://app.element.io. Click "Create Account."

While Matrix is federated and thus you could use the default matrix.org server, we strongly suggest changing your server to the one hosted by the Monero Core Team. Using another server greatly supports decentralization 😃
Click on "Edit" near the upper right.

Click on the "Other homeserver" field, and type in "matrix.monero.social" as shown. Then click "Continue."

You must provide a username and a password. You may optionally also provide an email and phone number. We recommend providing an email but not a phone number. You may use any email you like, or you can not use one at all. The email is used solely for recovering your account if you lose your password. Make sure to use a very strong, unique password and keep it in a safe place!

If you provided an email, you will need to click on the link that was sent to it. Otherwise, you will not see the screen below.

After verifying your email, you should see that the same email verification window as before now says "Registration Successful". Click "Log in."

The homeserver on the login page should default to the correct matrix.monero.social homeserver. Provide your username and password, and then click "Sign in."

You are now logged in! You should see the below layout. Most people will want to start by joining existing chat rooms, though you can also direct message others and create groups. In this example, we will join existing chat rooms. Click "Explore Public Rooms."

That will bring up a list of public rooms in the monero.social Matrix server. Join the ones that interest you by clicking the green "Join" button on each that you want to join.

This is as far as this guide takes you! You now have an account and know how to join existing rooms. Say hi in one of them!
Logging back in
To log back into your account on Element web, first go to https://app.element.io. Then click "Sign In."

Click on "Edit" near the upper right (if you used the monero.social homeserver).

Click on the "Other homeserver" field, and type in "matrix.monero.social" as shown. Then click "Continue."

Provide your username and password, then click "Sign in."

You should now be logged in!