It's to show you have permission of the property owner to have firearms there. Ask for rent receipts showing the physical address as well as your mailing address.A rent receipt should work. Generally, employees have up to 90 days to establish City residence if they are residing outside of the City at the time of appointment. This booklet explains many of these laws you need to know and provides resources where you can find more information about landlord and tenant issues. You can apply for a Certificate of Residence no earlier than sixty (60) days before the start date of the semester or more than thirty (30) days after.