How do I use a group QR Code?

1- Share Group QR Code

A maximum of 100 users can scan a group QR Code to join a group, including users that the group owner previously invited to the group. When there is 100 members in the group chat, you can’t join the group by scanning the group QR Code.

2- View/Send Group QR Code

Select a group chat and click the people icon on the top right to enter the detail screen. Click「Group QR Code」and tap the icon on the top right to select「Save to Phone」

Source: WeChat Help Center