I have a large file that needs to be downloaded by a client, if i put a download button on my site how do i link it?
If you zip the file you should be able to just link it like any other hyperlink and it should open a download screen instead of a browser window.
It sounds like this is a one-time file transfer. If so, have you considered using FTP? FileZilla is free and easy to use, both for you and your client.
There is also a free version of You Send It: