Why am I best for the Job of Customer Relations Officer?

You should know what is required for this job and also know how you qualify.

Strigner

What is the job description? What duties will you be expected to perform? Do you have the education and knowledge they require to do this job? What do you bring to the table that others may not?

You need to do your research, see if you qualify for this position, if you have the necessary tools to do the job. If you do, then you have to showcase those skills in your resume and cover letter so that the company knows what you can do and why you're the best person for the job.

You're selling yourself to them, but first you need to make sure you have what they're looking for.

Good luck.