Us PC folks aren't getting Destiny 2 for a month after the console folks, but you can get an early start on setting up your accounts. Bungie has gone and setup a way to link your Bungie.net profile to your Blizzard account.
If you don't remember, Blizzard will be distributing and handling the network communications for Destiny 2 and it will not be appearing on Steam. Part of the reason is so they won't have to pay the 30% to another person with Bungie and Blizzard both a part of Activision.
By the way, pre-load for the beta starts today for Xbox One and PlayStation 4 pre-order folks or those who got a key. PC beta will be in August sometime.