What's the name of the command?

What is the command in minecraft in a command block that if you activate the block in the screen is the game starts in 3.2, 1 z.b

You can do that by placing a Redstone Torch on the block, which then triggers a Commandblock using Redstone, which then issues a title (/ title).

I recommend a title generator on the internet.

I guess with / title

Just look up the associated syntax on the Minecraft Wiki.