Uses of affidavits include:

• To allow evidence to be gathered from witnesses or participants who may not be available to testify in person before the court, or who may otherwise fear for their safety if their true identities are revealed in court.
• To obtain a declaration on a legal document, such as an application for voter registration, that the information provided by the applicant is truthful to the best of the applicant's knowledge. If, after signing such a declaration, the information is found to be deliberately untrue with the intent to deceive, the applicant may face perjury charges.