Maintain a corporate address book online. Create documents the way you always have. No special software is required. Note that it is best to think through your document and delivery needs upfront. A professional job requires adequate preparation, and planning beforehand will reduce time, energy and the possibilities for mistakes.
Registration is free.
You can set up an account any time and have it ready and waiting when you need it. It won't finance your website, but may provide a useful resource to your clients.