Want to declassify some documents like a boss? Here's how:
1. Be the president of the United States.
2. Think really hard about declassifying them.
3. Say "It's declassified" out loud or on TV.
4. Ignore any pesky rules or processes.
5. Enjoy your freedom of information!
Congratulations, you have just declassified some documents!
I mean yes. Head of the executive branch does come with authority over the executive branch.
Well until the term expires or you cross Congress badly enough that they were movie from office.