Questioned Document is one of the significant components in forensic science. This chapter explores the basic principles of handwriting, signatures, and the factors affecting them. Some of the commonly encountered questioned documents generally include paintings, rent receipts, prescriptions, letters (suicide, love, or threatening), security documents such as passport, ID cards, and currency notes. Tampering is one of the burning issues which are easily achieved by the means of addition, alteration, erasure, obliteration, charring, and adopting secret writings. The challenge faced by the experts in recognizing the sign of tampering, forgery, and the employment of examination technique to it is a prevalent dispute. The Questioned Document Examination (QDE) will be valuable for the students, police officers, investigators, and attorneys as they will gain information regarding the court and the procedure of litigation. They will also achieve information regarding the guidelines in forensic document examination and the role of the expert in questioned document examination. The focus on the admissibility of various questioned documents in the court of law and the associated laws is being expounded.