Answer:
First, they are the most visible and authoritative spokesperson for the majority party in the House. Speakers articulate an agenda and explain legislative action to other Washington officials as well as the public. They oversee House committee assignments and collaborate with the powerful House Rules Committee to structure floor debate.
Second, the speaker manages business on the floor and navigates legislative rules, structuring House debate in a way that will advantage their legislative priorities. Adherence to strict rules and procedures is necessary to overcome the difficulty of managing a large legislative body like the House of Representatives.
Third, the speaker oversees everything from accounting to procurement for the House.