To create a World of Warcraft Community:

  1. Open the Guild and Communities window (hotkey is J by default)
  2. Click on Join or Create Community
  3. Click Create a World of Warcraft Community 
  4. Enter a name for your community, a Short name (up to 6 characters), and a description
  5. Select icon that represents your community
  6. Click Create Community
To join a World of Warcraft Community, you must have the community's invitation link or code. If you have the link, click it and follow the instructions on the page. To use a code or link in game:
  1. Open the Guild and Communities window (hotkey is J by default)
  2. Click on Join or Create Community
  3. Enter the community's invitation link or code in the space provided and click Join

Note: Communities are not available in World of Warcraft Classic.