How did Anakin become a force ghost?

And it’s very interesting to me that Luke definitly trained to become one but after what happened at the temple completely abandoned it.(Which to me seems completely reasonable for the character given how much loves his friends and family) But as he’s sitting on that rock in front of the suns he reconnects with that training. And it seems like he’s looking to the future as he did on Tatooine rather than embracing death. His final moments are pretty great to me, but I wonder what happens in universe to Anakin.

Maybe Qui Gon’s voice came to him as it did with Yoda, letting him know how this could be accomplished even though Vader would reject it. Yet in the end would achieve it since he would know how it would be done.