Minecraft wiki entry for spawnpoint, associated text: Specifies the coordinates of the player's new spawn point. If not specified, defaults to the position of the specified player(s) in Bedrock Edition or the command's execution in Java Edition.
In Java Edition, it must be a block position composed of <x>, <y> and <z>, each of which must be an integer or a tilde and caret notation.
In Bedrock Edition, must be a three-dimensional coordinates with floating-point number elements. Accepts tilde and caret notations.