Resume template is the best option to design a resume. With the use of such templates, you can save your time required for including different sections for your CV, including the details in the corresponding sections, choosing the appropriate format, etc. These templates can be downloaded for free, edited and filled with your details.
Functional template is used when the applicant has considerable gaps in his work history. These gaps make a bad impression on employer and hence should be hidden. This format is more focused on the skills rather than the experiences of the applicant.