Link tracking can be applied to a project, mailing or version. If wanting to apply it to the whole account, you can can go to the link tracking page and set it in the link group section.
Taxi for Email offers a variety of options for adding tracking to your email links.
You can set up standard or custom tracking strings, which are automatically appended to all links.
You can track links by type, e.g. images, or you can track and edit on a link-by-link basis.