In NAV 2016 on Posted Sales Invoice screen option is provided to send documents to multiple source like
- Send to Printer ,
- Send document by email to customer,
- Save it to disk
- Send document to exchange service.
One can find the option on Posted Sales Invoices as follows
In this option user can send document to directly to printer or send document via email or save the document to disk in PDF format. This will basically reduce the work the save the file in PDF and then attach it to email and send to customer.
In the above option when user click on option where one can select to Use ‘Yes (Use Default Settings)’ or ‘Yes (Prompt for Settings)’.
1) Yes (Use Default Settings):- This will use default settings of system for printer,email etc.
2) Yes (Prompt for Settings) :- By selecting this option user can configure
For example if user selected email option for prompt for settings then screen will look like
In this screen user can add details required options and send email .If you selected ‘Edit in Outlook’ so email will open in default outlook client and you can edit the message 
Cheers…
