Usually an appointment letter follows a verbal offer of employment. If you have been offered employment, then the letter is definitely official. If you haven't, it should be checked out.

Yes, as a condition of employment with ShopRite, I am willing to undergo a criminal background and employment reference check.

A testimonial is a statement endorsing a person or product that typically reflects personal experiences, while a letter of reference is a formal document written by someone who can attest to an individual's qualifications, character, or achievements. Testimonials are often brief and informal, while letters of reference are detailed and structured, often requested for employment or academic purposes.

No at present not valid for employment