Complete Post-Arrival Check In e-form. 3. Writing an employment offer letter isn't easy; you must create a compelling agreement that favors both the candidate and your company.Offer Letter (Recommended) – After a job offer has been made and accepted, an offer letter may be completed and given to the new hire. How Much Does an Offer Letter Cost? The average cost (i.e. If you have made up your mind then write a simple letter telling them that you have decided to withdraw your acceptance letter.