From the Document: "Speaker Pelosi announced last week that the House 'is moving forward with an official impeachment inquiry.' Although the Speaker's statement did not address precisely how the House will proceed, it is noteworthy not only because the House has so rarely investigated a President for the purpose of impeachment, but also because an impeachment investigation has usually been an early step in a constitutional process that could ultimately result in the removal of the subject of the inquiry from office. This Sidebar identifies procedural options for the House as it proceeds with an impeachment investigation. The Sidebar also describes some of the ways in which an impeachment investigation, as compared to a more traditional investigation for legislative or oversight purposes, might bolster the House's ability to obtain, either voluntarily or through the courts, information from the executive branch. The Sidebar also briefly describes possible future steps that might follow an impeachment inquiry, including possible action by the Senate."
CRS Legal Sidebar, LSB10347
Congressional Research Service: https://crsreports.congress.gov/