Outlined text has been converted into a vectored format.
Vectored text can be scaled infinitely without any loss of image quality. That means your text will appear smooth and crisp at any size or resolution and will print clearly on your graphic. Also, it's possible to open and print your artwork correctly without needing the actual font file used.
When submitting your Artwork for print, one of the requirements is to outline your text otherwise the printer will reject it as a fail safe to ensure you have the best resolution for you graphics.
Note: Once text is outlined, it can no longer be changed / edited.
Click here to view all Artwork Guidelines
Note: Keep a copy of the original file so you can edit the text in the future