When you notice an interesting vacancy online or elsewhere, first read the job advertisement carefully and think about the kinds of skills and competence the employer is looking for. Consider how your skills meet your employer’s wishes and requirements.
In general, when you apply for a job, you send the employer a job application and CV. Write the application and CV in the same language that was used in the job advertisement. Write a new application and update your CV every time you apply for a new job.
The purpose of a job application is to arouse the employer’s interest so that they will invite you to an interview. The application is your reply to the job advertisement. Respond to the wishes and requirements that were mentioned in the job advertisement. Highlight the things that are important to the task. Give concrete examples of your skills. Convince your employer that you are suitable for the task.
A job application is usually less than one page. Ask someone to read and check your application.
For more information on job applications, testimonials of service, study certificates, salary requirements, recognition of your own skills and qualifications etc., see here.