When emailing work orders or invoices directly from Camelot, realize that it will send just a text message that is a summary of the job. You don't really have any control over the formatting of the message.
That being the case, what we recommend actually for emailing work orders or invoices to clients is to get the Adobe Acrobat program (not just the reader, but the actual program - costs around $80). Then when you go to print an order or invoice, one of your printer choices will be the Adobe PDFWriter, and you can choose that, and then instead of it printing to a printer, it creates an Adobe PDF file of your invoice. And so then you can attach that file to an email to the client. This makes for the nicest overall look. There is also a free program for writing PDFs available at http://www.cutepdf.com.
If you would rather just email a text version of the orer or invoice directly from Camelot, you first need to be sure that you have entered your valid SMTP mail host name on the Email tab of the Misc/Setup > Company/Misc Info setup screen.
Then go to the Print Forms screen (from main menu Navigator choose Accounting, then Print Forms) and on the Invoices tab, you can select invoices, and then right-click anywhere on them and choose to Email the selected invoices. Of course it can only email invoices to client's that have an email address on file, so keep that in mind. You can enter a message that will be at the top of each email that is sent.