A couple of months ago, the now independent Bungie announced that it is making Destiny 2's base free-to-play, and also that Steam will be the game's new home for PC players. Blizzard's Battle.net version is being axed on October 1, the same day that the Steam version will go live, and although there's plenty of time left on the counter, the transfer process can now be started.
The transfer means that the Destiny 2 player's game account on Battle.net with their expansions, levels, silver, and anything else they own will be attached to their Steam account, all prepared for the migration on October 1. So, anyone who doesn't want to start over from scratch with the free-to-play New Light variant is advised to begin moving before that date.
All that's required for completing the process is logging into Blizzard.net and Steam on Bungie's PC Move portal, and letting the magic happen behind the scenes. The website will have a popup saying "You are ready to move to Steam for Shadowkeep launch" if everything goes to plan.
The Destiny 2: Shadowkeep expansion also lands on October 1 alongside the free-to-play New Light launch. The expansion is already available for pre-purchase on Steam for $34.99. Also, Bungie is adding cross saves support to the game tomorrow, August 21, so players on any platform can jump around to a PC or console of their choice and carry over their characters.