You want to give at least a two weeks' notice. Learn how to write a professional resignation letter with our stepbystep guide including 15 resignation letter examples for various situations.The Frequently Asked Questions (FAQs) provided below highlight topics and specific questions that are often asked of the Illinois Department of Labor (IDOL). Learn how to write a resignation letter with a notice period. Every resigning employee shall be urged to indicate in the Resignation form the reason for leaving. Every resigning employee shall be urged to indicate in the Resignation form the reason for leaving. The standard notice period is two weeks. 4. Reasons for Resigning. Some states mandate a specific form that employers must provide to an employee upon termination. An email with your last day worked and intention to resign will suffice.