If you have a new project, set up the client contact first and then add it to the new project. If you need to add a client name to an existing project, you still have to set up the client contact first. Then you can go back to the project and click on the Reassign button. This takes you to a Search screen, where you can type that person's name an click Reassign. This assigns the client to your project.
To add a client's title and company to your ArchiOffice/EngineerOffice invoices:
1. Go to the client's Contacts record in ArchiOffice and add a new tab called 'Billing'. 
2. Enter the relevant information for the client such as First Name, Last Name, Company, Title (in Address 1), Street Address and Suite # (in Address 2), City, State and Zip.
3. Make sure this tab also has the Billing check box selected and then click Save.
When you run an invoice for this client, you will see this information on it. 
If this doesn't work for you the way you want, you can request a custom invoice template from customreports@bqe.com.