Ind. Code § 28-1-5-3
Every corporation shall maintain an office or place of business in this state, which shall be known as the "principal office", and which shall be located in a county in which the corporation conducts business. The post office address of the principal office shall be stated in the original articles of incorporation, at the time of the incorporation. Thereafter, the location of the principal office may be changed at any time or from time to time when authorized by the board of directors and approved by the department, by filing with the secretary of state on or before the day on which the change is to take effect, a certificate signed by the president or a vice president and by the secretary or cashier of the corporation and verified by one of the officers signing the certificate, stating the change to be made and reciting that the change is made pursuant to authorization by the board of directors.
IC 28-1-5-3