Hi Karthikeyan Masialamani ,
When you are working on tableau , instead of focusing on the the format keep your focus on story telling -Use your data to tell a story .
I would like you to check few white papers shared on tableau site.
But if you are really bothered about the perfection and formatting ,please check this link .
But always keep in mind the way you are presenting your data (i.e. charts , graphs etc) is more important than the fonts you are using .