Ind. Code § 32-26-3-1

Sec. 1. Adjoining property owners who elect to erect, repair, maintain, or pay for fences separating their lands in a manner other than that set forth under this article shall do so by written agreement. When the agreement is signed by the adjoining property owners, the agreement must be recorded in the office of the recorder in the county or counties in which the adjoining properties are situated.