Indiana code § 1-1-2-1 provides:
Sec. 1. The law governing this state is declared to be:
Fourth. The common law of England, and statutes of the British Parliament made in aid thereof prior to the fourth year of the reign of James the First? [FN1] (except the second section of the sixth chapter of forty-third Elizabeth, the eighth chapter of thirteenth Elizabeth, and the ninth chapter of thirty-seventh Henry the Eighth,) and which are of a general nature, not local to that kingdom, and not inconsistent with the first, second and third specifications of this section.
Leone v. COM'R, BUREAU OF MOTOR VEHICLES, 933 NE 2d 1244 - Ind: Supreme Court 2010 states:
The very nature of a common-law name change means it does not require a court's approval..All states have enacted similar statutes, and all but two have concluded that they do not abrogate but instead supplement the common law.
Statutes obliging citizens to engage in some formality when they invoke government processes by applying for benefits or identification cards neither obliterate common-law usage nor are they driven by them.
In re Resnover, 979 NE 2d 668 - Ind: Court of Appeals 2012 states:
Under common law, a person may lawfully change his or her name without resort to any legal proceedings where it does not interfere with the rights of others and is not done for a fraudulent purpose. Leone v. Commissioner, 933 N.E.2d 1244, 1252 (Ind.2010). A person effects a common-law change of name by usage or habit. Id. Therefore, the very nature of the name change means that it can be effected without court approval.
In re Doe, 148 NE 3d 1147 - Ind: Court of Appeals 2020 states:
At common law, a natural person has long been permitted to change his or her name without resort to any legal proceedings, as long as the name change does not interfere with the rights of others and is not done for a fraudulent purpose. See Leone v. Commissioner, 933 N.E.2d 1244, 1252 (Ind. 2010); Petition of Hauptly, 262 Ind. 150, 312 N.E.2d 857, 859-60 (Ind. 1974); Resnover, 979 N.E.2d at 672.