The safe zone is an area of a design that is free from any elements that could be cut off or otherwise obscured during the printing process. Typically, the safe zone is defined as a margin of 3mm from the edge of the page.
In order to ensure that your artwork is not cut off or otherwise obscured, you should make sure that any important elements (such as text, images, and logos) are placed within the safe zone. You can define the safe zone on your artwork by using margins or guides in your design program that lie 3mm in from the edge of your page.
Using a safe zone can help you avoid potential issues and ensure that your artwork looks its best when printed.