How can i point an object toward my cursor?

(How can i point an object toward my cursor?)
I’m developing a game called A Fight In The Dark, and i want the sword/gun mechanics to work based on the player’s position and the cursor’s position. does anyone know how?
The blade needs to be close to the player at all times
The blade also has to point toward the cursor

use node3d Node3D — Godot Engine (stable) documentation in English look_at(Vector3 target)

but Vector3 target is from canvasItem’s global mouse position CanvasItem — Godot Engine (stable) documentation in English
since the canvasItem’s Global mouse position is in Vector2, then you need to convert it to vector3 first, i think.
the canvasItem could be a Control node with full rect to cover whole screen
can emit a signal to tell the current global mouse position as a target and feed it to the node3d of your sword