It can be a letter, stationery , or any types of template containing the information that you want to send to the vendor or to the customer.
the documents should contain special field codes that you insert which names and addresses reference will be replaced with the information from the data source
2 I think because 2 I think is binary I’m sorry if this is wrong
4, 1, and 3
The last one I am going to say three because I know that friends show other friends so I wouldn’t call that “private”
You add all the addresses into excel and and do mail-merge with the invitation. Adding the 100 addresses is probably a lengthy process but once this is complete you can just add on addresses and once a year or whenever you have to mail something to everyone, it's a only mouse-click.