The U.S. Constitution does not define in details how states are governed beyond the mandate that all states have a “republican form of government." As such, it is left to each State to formulate and adopt its own state constitution. In fact, four colonies adopted constitutions even before the Declaration of Independence was proclaimed on July 4, 1776. By 1780, all of the original 13 states had adopted their first state constitutions.
State constitutions address a wide array of issues deemed by the states to be of sufficient importance to be included in the constitution rather than in an ordinary statute. Because they are more detailed regarding the day-to-day relationships between government and the people, state constitutions are typically longer than the U.S. Constitution.
Often modeled after the federal Constitution, state constitutions typically outline the structure of the state government, including an executive branch headed by a governor (and often one or more other officials, such as a lieutenant governor and state attorney general), a state legislature, and state courts, including a state supreme court. They also provide the general framework for what each branch is supposed to do and how it should go about doing it. Additionally, many other provisions may be included, including provisions specifying the structure of local governments within the state.
Many states have had several constitutions over the course of their history, and state constitutions are more frequently amended than the U.S. Constitution. In fact, some states allow amendments to their constitution by public initiative.