What is a letter of application primarily used for?

A letter of application is primarily used to communicate with a prospective employer regarding a job position. It serves as an introductory document where the applicant expresses interest in a specific role and outlines their qualifications, skills, and experiences relevant to the job. This letter is an opportunity for the candidate to make a strong first impression and highlight why they would be a good fit for the position they are applying for.

In contrast, the other options refer to different circumstances. A formal notification of a job offer is used by employers to extend a position to candidates. A request for a salary increase pertains to discussions about compensation with current employers, while a notification of resignation informs an employer that an employee is leaving their job. Each of these serves a distinct purpose that does not align with the primary function of a letter of application.