How my two kids can play together on Xbox one

Some couch co op games.

Minecraft

Overcooked

LEGO games

I will definitely quote what RandyAU93 said.

For gold, purchases and other subscriptions keep everything on one single account. All other account will share the licenses and subscriptions.

It's better to have separated accounts for each users. And this is totally free!

You will avoid them going in conflict over gamesaves, online friends and stuff like that.

It really depends on the game. Some games you can play multiplsyer on one account like some of the lego games. Some games you will need multiple accounts .It really depends on the game. Good luck and i hope they have fun.

Each user will need their own (free) Microsoft account. This gives each child their own online presence, their own game saves, etc. Since they'll be using a single Xbox One, the Home Xbox feature will allow one user who has Xbox Live Gold to cover all the
users on that console.

As to playing at the same time, that will depend on the game. Not all games have that ability (called "local multiplayer", "split-screen" or "couch co-op"). You will need to read the descriptions of the games to determine if they have that option.

Hi, You would need local co-op games for them to play. You can find many of these in the Xbox game store.