Bedford has an "open" town meeting, which means that all of Bedford's registered voters are eligible to come to Town Meeting (TM). Some towns in Massachusetts have a "representative" town meeting and elect their TM members.
In the government structure of Bedford, registered voters attending TM are the "legislators." Town Meeting members are vested by the Commonwealth of Massachusetts and Bedford's Charter with the traditional powers of the legislative branch of any level of government: the power to make laws (in this case, called By-laws) and the power to approve the expenditure of money. No money can be expended by the Town without the approval of Town Meeting. No general or zoning laws can be enacted by Bedford without the approval of Town Meeting.
You can read these Zoning Bylaws, General Bylaw, and Bedford's Charter on the town website.