In Illustrator, you can change the background color of an object by using the Background property. This property is located in the Object Properties panel of the Preferences window. To change the background color of an object, follow these steps:

  1. Open the Preferences window and click on the Background tab.
  2. In the Background section, you will find a list of options for changing the background color of an object. The options that you will most likely want to use are White, Black, and Gray.
  3. To change the background color of an object, select one of these options and then click on OK to close the Preferences window.