A button appears on the sign that your friend is on, and if you press it, a message shows up for the person you invited that says “[your username] wants you to join them in [map you’re in]!” Then, the friend can walk over to your map.
Notes:
• if you’re in a private world, it’ll say you’re in [world owner]’s private world. In you’re in a community world, it says you’re in “community world [code]” However, if they’re unable to join the map you’re in, it won’t let you invite them.
• if possible, it should let you add an extra note to the invite, in case there’s a special reason to invite them. It’d say something like: “[your user] invited you to join them in [map]! They say: [message you added]”
• if possible, it should also tell the friend if the server is full, and notify them again when a space opens. It’d say something like “[your user] invited you to join them, but the server is full. We’ll let you know when you can join!” And say something like “[your user]’s server has a space open, go join!” When a player leaves.
• finally, if a player invites you too many times within a set period of time (probably about 3 times in a minute), you’ll get a notification saying “[friend] is spamming you with invites. Would you like to temporarily block invites from them?” This will stop that person from inviting you for a while. (I think 5 minutes is good)