Bungie has finally detailed Destiny 2's long-awaited transmog system, and it sounds like a parody of the game's mission loops, management of multiple materials and optional microtransactions.
First up, here's the basic gameplay loop needed to grind out the materials you'll need to alter the appearance of eligible items, as per Bungie's blog:
Black Armoury vendor Ada-1 has taken on transmog duties in the Tower, and you'll visit her to cash in your materials and acquire Synthcord bounties. These can relate to playing all parts of Destiny 2 - Strikes, Cruicible, Raids, Gambit etc.