What is a letter of application primarily used for?

A letter of application is primarily used to describe an applicant's qualifications and interests, particularly when seeking a job. This document allows the individual to showcase their skills, experiences, and motivations relevant to the position they are applying for. It serves as a personal introduction to potential employers, highlighting how the applicant's background aligns with the job requirements.

In this context, the focus is on conveying relevant information that distinguishes the applicant from other candidates. The letter typically includes details such as educational background, work experience, and specific examples that illustrate the individual's strengths and suitability for the role. It is an essential component of the job application process, complementing the resume and providing a narrative that can engage the employer.

The other options do not align with the primary purpose of a letter of application. Submitting a resignation or requesting a salary increase pertain to job-related communications that are not focused on applying for a new position. Informing about a job opening does not match the intent of the letter, which is centered on the applicant's qualifications rather than conveying job opportunities.