There used to be a day when you could create one generic resume and then blast it to a wide range of jobs you were interested in applying to. Even if you are using a resume service this practice of blasting is generally frowned upon. HR professionals are inundated with resumes and they want to see that applicants have read the ad and are responding directly to it. One-for-all type of resumes are easily spotted and are generally discounted by HR. So work with a resume service to see how you can best tailor yours for each job you are applying to.
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.
Remember you resume will be read by humans as well as by machines which will scan for the right keywords. So put some time and energy into your keywords when you write. Resumes must grab the attention of both the human and the computer scanner.
There are millions of resumes being uploaded to job sites and because of this job sites have an ongoing need for more and more web servers. Job sites earn revenue from recruiters and employers that are subscribers and not from job seekers so it makes sense to eliminate this cost and pass it on to the resume website provider. Since people manage multiple resumes in their profiles to apply for different jobs it would be better for everyone if job seekers had multiple links to different resume pages instead of resume PDFs. The storage cost to job sites is eliminated and job sites can reduce their fees to subscribers.
Functional format is best for those who are switching their career or have large employment gaps on their resume. In this format, you dont have to list the joining or resigning dates of the previous employments. Functional format will hide your employment gaps or your job switching.