The resume writing service does not require knowing anything about you. All they ask you to do is fill out a standard online questionnaire and maybe submit your current resume. A competent service needs you to fill out a questionnaire; however it does not end with this. They contact you and ask for numerous other details about your career and achievements that they need to create an effective resume.
The template of the resume which is actually the outline or the structure of the resume decides the positioning of every element of the resume. If this positioning is clear and clean with an equal weightage given to every element it appears that there is a flow in the format and so the resume appears attractive. Such a resume neither looks like a piece of art which shows that you were keen about the outline of the resume rather than the content nor does it appear as an essay.
Functional resumes are good when you have little to zero work experience (or new grads). This type of resume allows you to showcase skills that fit in with the job requirements. Fair warning: most recruiters and hiring managers dont like this format and feel as though you may be hiding something. If you have a chronological resume you do not want to have one part chronological and one part functional because it will throw off the entire formatting and may confuse the employer about your skill set.