If you are an admin of a group, you can invite users to join the group by sharing a QR code or an invite link. Anyone with the QR code or the link could join the group without further approval.

To share QR code:
Go to the group chat you wish to invite others to join > tap “v” button on the top right corner on title bar > Info > Under “Members” section > tap “Invite with Link” > tap on the QR code at the bottom > You can save or share the QR code

To share invite link:
Go to the group chat you wish to invite others to join > tap “v” button on the top right corner on title bar > Info > Under “Members” section > tap “Invite with Link” > Select language of the invite link > You can share or copy the invite link