61 Pa. Code § 117.9
Persons filing returns should use the envelopes and preaddressed prescribed forms furnished to them by the Department. A taxpayer shall not be excused from making a return, however, by the fact that no return form has been furnished to him or the one that was furnished becomes lost or damaged. Taxpayers not supplied with or in possession of the proper form should make application therefor to the Department listing their name, address, and identification number and sending such request to the Department of Revenue, the Personal Income Tax Bureau, Harrisburg, Pennsylvania 17127. Such request should be made in ample time to have their returns prepared, certified, and filed on or before the due date. Each taxpayer should carefully prepare his return and set forth fully and clearly the information required to be included therein. Returns which have not been so prepared will not be accepted as meeting the requirements of this article.
61 Pa. Code § 117.9