Follow these simple steps!
Log in to Patreon and make sure you are subscribed to the Mini-Chad, Chad or GigaChad tier. I recommend that you do this process on a computer.
Go to the Patreon home page.
Find and click the "Settings" button (under "Quick links" Top Left)
Click on More and then Connected Apps from the menu bar
Enter the email address or phone number you use to log in with Discord and your password and click the Login button
Click the Authorize button
You've successfully linked Discord to Patreon! You may need to refresh the page
What if I can't see the "connect to Discord" button?
Wait ten minutes: the server might need some time to update with your details.
Make sure you're subscribed to a tier that includes Discord Benefits.
Close and re-open Discord.
You can also find a detailed guide from Patreon here.