Perhaps when he was president, or are you one of those MAGA's who thinks that Trump is STILL president and therefore has retained all of his 'powers'?
That being said, even though the president is able to declassify documents, he can't so by a simple wave of his hand, or thinking hard about it. There's a process with specific steps that have to be completed, including a review by the agency that first classified the document. And while the president may have the final say, these other agencies and groups do have a right to make recommendations for things like redactions and such.