How are new states created from territories? and new states from pre-existing states?

Answer 1

A new state comes into being when the territorial legislature sends a resolution to the U.S. Congress asking that body to pass a Bill of Statehood to admit the territory to the Union. So far, only two new states were carved out of the land of an existing state. The first was Maine, which was formed from a part of Massachusetts that existed as a colony before the American War For Independence. The second was West Virginia, which was admitted to the Union during the War Between the States and was formed from a part of Virginia.
Only one state currently has a provision in its Bill of Statehood to permit it to divide itself into other states. That's Texas, which has the right to form five states from within its current boundaries.