Manuscript needs to be formatted as per guidelines given on Journal website wherein author wishes to submit paper. Every Journal has its own formatting style which needs to be followed to avoid rejection at editor's desk.
Are you asking for websites/agents who do this for you?
As Rohit Bansal mentions, every individual journal has its own individual requirements and is slightly different to other journals. I tend to make those modifications by myself to save money! But I am sure there will be websites/agents that can do it for a fee.
The other major advantage (of doing by self) is that it will be done by end of that day, for example, and I know exactly where I am up to and I do not have to wait and guess if somebody else is doing it...~