I can t play with Friends in minecraft,when i join his world appears an error saying,its...

Are you playing the same version? Your versions have to match to be able to play together. You might have them check and then check the one you are playing on. One of you might need to update.

To add on to what Mikeysooerfan said, It is possible that one of you might be on the Xbox Insider Preview version of Minecraft in which you get updates ahead of time and cannot play with people that are on the version that is currently released.

sorry im late to respond.ye i play regular multiplayer but my friend cant join they dont receive error code its just say unable to connect to the world and i can play with my other friend but not with him and i cant even join to his world too.sorry for my bad english

i hope you can reply this fast

So... it appears you're having problems connecting to your friends worlds in Minecraft for Windows 10.

I would have them check their in-game settings in Minecraft under the main menu there, and make sure that Online play is enabled. Sometimes this is switched to being disabled and therefore they cannot join any online games and friends cannot join their game
either. Both you and your friends should check in Minecraft settings and make sure that Online play is enabled and friends are allowed to join. Then you can select which permissions you would like to enable for your friends when they join your world after
that.

If any of his friends play minecraft and they have a world that anyone can join then he will be able to play with them