Former President Joseph R. Biden Jr. spoke to The New York Times by phone on Thursday about clemency actions he granted toward the end of his term. Mr. Biden did not personally sign the official warrants recording those decisions; rather his White House staff used an autopen device to do so.

President Trump and his allies have since called into question Mr. Biden’s mental acuity and seized on the use of the autopen. Mr. Trump has denounced the pardons and commutations as illegitimate and claimed that Mr. Biden’s staff conspired to run the presidency in his name using the device. Both the Justice Department and congressional Republicans have opened investigations.

Mr. Biden granted large batch commutations to reduce the sentences of three categories of federal convicts: shielding about 1,500 people who had been serving home confinement since the pandemic from being forced back to prison; reducing the sentences of about 2,500 nonviolent drug offenders to what they would have received under current policies; and turning the sentences of 37 of the 40 inmates on death row into life without parole.

He also granted pardons to several people whose cases have received political attention, including pre-emptive pardons to people who had drawn the ire of Mr. Trump.

Among them were members and staff of the House committee that investigated the Jan. 6 Capitol attack along with Capitol Police officers who testified before the panel, Dr. Anthony S. Fauci, the retired Gen. Mark A. Milley, the former chairman of the Joint Chiefs of Staff, and members of Mr. Biden’s family.