The grand jury subpoena — sent to an unnamed witness last month and seen by Axios — asked for emails, texts and handwritten notes linked to those people, according to the report.
Ten people are targeted in the subpoena, including the president and others who have worked with him. Among them are outgoing White House communications director Hope Hicks, Trump's personal lawyer Michael Cohen and the president's former strategist Steve Bannon, Axios said.
Mueller requested all communications since Nov. 1, 2015, according to the report. That's five months after Trump announced his presidential campaign.
Trump's lawyer Ty Cobb did not respond to Axios' request for comment, or to an email from CNBC.