A Manager is a decision maker in a company. Together, all Managers form The Board of Managers, which is the governing body for a company. Every year at their annual meeting, the Members of the company elect Managers to the Board. Delaware law requires that you have at least one Manager in a Manager-Managed Company. If you have more than one Manager, we recommend appointing an odd number of Managers so you don’t end up with a board deadlocked 50-50 board for a major decision.
Each Manager normally has one vote, though you can change this. All major decisions need to be ratified by the Board. You will need the Board's approval to sell your company. You will need the Board's approval to raise a round of financing. The Board appoints officers of the company like a CEO and approves all matters of major strategic importance.
So what is the typical setup?
A good number of Delaware LLC’s are Manager-managed. This means that Managers make all the decisions about the day-to-day business of the company and make the major decisions. If you like you can appoint Officers as well, and one person can fill more than one role. A Founder can serve on the board of Managers and be an officer of the Company (very common).
Here’s a typical setup for a two founder startups: