An external contact is a member other than the WeCom member. Company members can add members of other companies or WeChat contacts as WeCom contacts for further communication.
The external contact name will be followed by a suffix @, while the accounts in the same company will not.

After adding an external contact, you can start a private chat or group chat. You can receive and send texts, images, voice messages, business cards, files, chat history, locations, favorites, H5 webpages, and mini programs.