To share a group, your group must be public. You can make a group public when creating the group or when updating a groups settings. If your group says “Private”, then click on the gear to edit your group’s status.
Once your group is public, you can share your group with either a direct link (good for websites, Facebook, Twitter, etc) or with a QR code, which is scannable by all conventional smart phones.
Important: Both the link and QR code are unique to your account. If you change a group from Public to Private, players will no longer be able to access that group even if they have the link or QR code.