This is complete nonsense. The link clearly states: The conservative Heritage Foundation’s Oversight Project uncovered the situation. This is the same outfit behind the toxic 2025 project that Trump supposedly knows nothing about.
Snopes fact checking site says:
The Oversight Project, in its X post, claimed it "gathered every document we could find with Biden's signature over the course of his presidency. All used the same autopen signature except for the the announcement that the former President was dropping out of the race last year."
Fox News claimed it "examined more than 20 Biden-era executive orders documented on the Federal Register's office between 2021 and 2024 and found each had the same signature." The Federal Register is the U.S. government's daily publication for executive orders and other official documents.
While it is true that many of Biden's executive orders carry a signature matching the one posted by the Oversight Project, the National Archives, which runs the Federal Register, said in an emailed statement that official documents published in the Federal Register use a copy of the president's signature that "comes from one graphic file."
"At the beginning of each administration, the White House sends a sample of the President's signature to the Office of the Federal Register, which uses it to create the graphic image for all Presidential Documents published in the Federal Register," communications staff at the National Archives wrote.
As the Federal Register's digitized documents do not represent what the signature looks like on the original documents, the Oversight Project's claim lacks credibility.
Neither the project nor Fox News provided evidence that these are autopen signatures, other than the fact that the purported autopen signature looked different from the signature Biden used in a letter announcing he would drop out of the presidential race in 2024.