Keep your garbage
You can’t just throw away your mail or delete emails on your server, that is a line they ask you as the President not to cross. The need to go through everything before it is deleted or tossed out, even destroyed. If you are someone who likes deleting junk mail, this may be challenging for you.
The President has to keep everything under the President Records Act, so it is the law of the land that they must abide by. This is so White House staff can sort and store everything after they are done with it. Remember you are a public servant and everything you do and say is put on record.