To join a server that doesn't require an invite link, simply select the search icon in the left sidebar and select a server or search for one using a name or keyword.
1. Open Discord and log into your account, if needed.
2. Click the plus icon in the left sidebar.
Select "Add a Server."
Select "Join a server."
Click "Join a server."
Paste in the invite link and hit "Join."
Paste link and click "Join."