To join a 'shared wallet' with another Bitcoin.com wallet user, you will need to either scan the QR invite code, or the creator of the shared wallet will have to send you an invite code.
To join a shared wallet by scanning the QR code, please follow the steps below:
Tap on "Scan" and scan the QR code with your phone camera
Your wallet should automatically take you to the "Join shared wallet" page
Enter your "username"; this will be your co-payer name
Tap on "Join Wallet"
Be sure you have cloud backup enabled. If not, you’ll need to write down the backup phrase for your new shared wallet and keep it safe.
If you lose the phrase, you’ll lose access to your shared wallet in the event you can’t access your phone.
Please see an instructional video here: