CRS report via FAS – Electing the Speaker of the House of Representatives: Frequently Asked Questions, updated November 26, 2018.
“This report briefly poses and answers several “frequently asked questions” in relation to the floor proceedings used to elect a Speaker of the House. Current practice for electing a Speaker, either at the start of a Congress or in the event of a vacancy (e.g., death or resignation), is by roll-call vote, during which Members state aloud the name of their preferred candidate. Members may vote for any individual. If no candidate receives a majority of votes cast, balloting continues; in subsequent ballots, Members may still vote for any individual”.