An offer letter typically shows the general terms of employment – pay, benefits, perhaps a bonus or commission plan, and a start date. A job offer letter isn't a contract.It doesn't require a signature and, as you've experienced, a signature doesn't guarantee a job. Customer: Who should sign an offer letter first? The employer or employee? No. It's different from a formal "Contract" of employment. Those become legal and binding upon joint signatures. Learn what to include in a job offer letter and use our ready made template. Offer letters aren't considered legal documents because these documents just propose a position to potential candidates. However, nothing is legally binding until an employment contract is signed.