Create a custom new document profile

Open the new document profile file you want to customize in the New Document Profiles folder located in these paths:

• Windows: %AppData%\Adobe\Adobe Illustrator <version> Settings\<locale>\x64
  
• macOS: ~/Library/Application Support/Adobe/Adobe Illustrator <version>/<locale>

Delete any existing swatches, graphic styles, brushes, or symbols you don't want to retain.

Do the following:

• Create any colors, patterns, and gradients you want, and save them as swatches. You can also import swatches from the Swatch Libraries into the default Swatches panel.
• Save any graph designs that you want in your files using the Graph Design dialog box.
• Create any graphic styles you want and save them to the Graphic Styles panel.
• Create any brushes you want and save them to the Brushes panel.
• Create any symbols you want and save them to the Symbols panel.
• Select the options you want as default settings from the following: View preferences (from the View menu), ruler origins, page origins, print settings (in the Print dialog box, File > Print), and actions.

Save the document profile file and restart Illustrator.