|There are two ways to do it, first you can host the file yourself or you can pay some one to host it for you. Hosting it yourself requires a computer with an FTP server installed that you can access from any where.|
FilesZilla is a good one. You need the server on your computer at home that hosts the file and the client on your computer in the office.
A hosting company makes space available for rent for people to use and access. This sort of thing is for people that wish to have their own web servers for for on-line back up.
There are plenty of companies offering an on-line backup service but they cost money.