Generally a job offer letter will show your new salary and that will help that you will be financially able to pay rent. Applying for an apartment?A short letter from your manager outlining your job title, salary, and how long you've been there will really help strengthen your application. It's essential that before you start your search for your rental apartment, you have a hard copy of your job letter. Another important NYC rental requirement is having proof of employment. I updated our family income to include my child's upcoming salary when they got a job offer.