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 Apple iOS with Element. Please refer to the other guides for Web and Android:
First, download the Element application:
https://apps.apple.com/us/app/element-messenger/id1083446067
After installed, open the application and click "Register" in the upper right.

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 😃
For server in this guide, tick "Use custom server options (advanced)" as shown below.

In the Homeserver URL field that appears, carefully type https://matrix.monero.social
as shown below (1). Then provide a username and password as indicated (2), then click "Register" (3). You must use a strong 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.
If you would like to provide a recovery email, fill it in (1) and click "Submit" (2). If you do not want to provide your email or phone number, click "Skip."

If you provided an email, you will see this prompt to confirm your email. You must open your email account and click the confirmation code to continue making your account. If you did not provide an email, you will not see this.

Logging back in
In the unlikely case you need to log back in, follow these steps.
Open the application. Tick "Use custom server options (advanced)" as shown below.

In the Homeserver URL field that appears, carefully type https://matrix.monero.social
as shown below (1). Then fill in your username (2) and password (3) as indicated, then click "Log in" (4).

You should now be logged in!