Your file will receive an automatic control. While creating or uploading your file using the Designtool, your file will be checked for the most common errors: Shapes, Bleed, RGB color range check, You will receive an error message if something is wrong on these points.
Not all errors will be detected during this automatic control. Some examples are: transparency, color ranges, missing fonts,..
If you aren't feeling sure about these points, please add the professional control.