The White House addressed their digital transition policy in a post at the White House blog, which is yet another digital property they've cultivated. The smooth transition of digital power has three goals according to the post. First, all materials will be handed to the National Archives and Records Administration (NARA), just like every president does with handwritten notes, faxes, emails, and other correspondence. The material passed to NARA will include all of his tweets and snaps (yeah, those don't disappear forever) in a variety of formats.
Secondly, the materials are to be readily available to the public "wherever possible." That means making sure all digital communications, like tweets, are available on their native platform. Obama's @POTUS account will be transitioned to @POTUS44. Similar transitions will happen with the White House's Instagram, Medium, and Tumblr accounts moving from "/whitehouse" URLs to "/obamawhitehouse." Accounts of the First Lady and Vice President will move to accounts with the "44" added to the end. Presumably, Joe Biden's Twitter Avatar will also transition to an image of a convertible burning out on the White House lawn.