All zoning applications may be filed in the online permitting system.
As soon as you have applied for your permit at the Department of Permitting & Inspections, you will be mailed a red "Z-Card" poster. This must be posted on your property in public view right away. Usually the Z-Card is posted in a front window or similar location so it can be easily read from the sidewalk.
This Z-Card serves as public notice that an application for a zoning permit has been made. This is not a permit or an approval to do anything. It is always a good idea to talk with your neighbors about your project beforehand so they are aware of what you are doing and are not surprised when the Z-Card is posted.