This guide will tell you how to play the Genshin Impact with your friends. Go through the guide and follow the step-by-step instructions.
If you want to play with your friends, then you must be on the Adventure Rank 16.
Once you reach adventure rank 16, you can invite your friends. If someone invites you, you will receive a request notification.
You can go to their world. You can explore the open-world / do challenges in the domain or fight an enemy.