The board of commissioners of such district shall elect one of their number chair and shall either elect one of their number, or appoint a voter of the district, as secretary, who shall keep minutes of all the district's proceedings. The board of commissioners may issue warrants of such district in payment of all claims of indebtedness against such district. Such warrants shall be in form and substance the same as county warrants and shall draw the legal rate of interest from the date of their presentation to the treasurer for payment, as hereinafter provided, and shall be signed by the chair and attested by the secretary of the board: PROVIDED, That no warrants shall be issued by the board of commissioners in payment of any indebtedness of such district for less than the face or par value.