Before printing mail envelopes or address labels, some basic setup is required (Main menu > Settings > Preferences > Printing mail envelopes and address labels):
Common setting for both mail envelopes and address labels:
Option Show Print Preview allows you to preview of an envelope or a label of the first selected address. Print preview window will be only displayed once, allowing you to verify the layout and correctness before the print.
Option Include Title will add contact title (Mr, Ms, etc.) if it is available in front of the name on the first address line.
Option Include Department, when checked, includes a line for a department for business addresses that have both Company name and Department. Company name and Department will be printed below First and Last name line, but above the Street address line. In general, including department line is optional. Unchecking this option may only be needed for printing address labels when label media size is limited, and complete business address does not fit into one label page.
There are two separate printer setting options for Envelopes (left panel) and Address Labels (right panel).
Both printer setting include selection of a printer from the drop-down list, and setting up paper size and source, orientation, and margins by clicking Page Setup.
Do not forget to save your setup changes.
Please note that you should have a corresponding printer driver installed and printer ready to print. The printer will use the paper source based on your printer setup. In case of any confusion on this matter, please refer to the printer manual, or adjust your printing preferences. When you print mail envelopes, you will get best results if you load envelopes in the manual feeder.
You can print mail envelopes with your return address on it, or without it (in case you use envelopes with a preprinted return address, or use preprinted adress labels).
If the option Print return address for envelopes is checked, you would have to choose which mailing address it should be:
Once the setup is done, you can print mail envelopes as follows:
Select one or more contacts from the table, click Print 
button in the toolbar, and select the Print Envelopes for N selected contacts option
Next, you will see the screen below where you can verify your selection, and specify the number of copies for each selected address. You can also preview individual address envelope before you print. If something in the address is missing or incorrect, you can click on the address and edit it in the opened editor. You can also adjust printer setting (page size, orientation) by clicking on the Envelope Printer information at the bottom.
When you click Print, the program will open a template (an *.rtf rich text file), populate one or both (Sender and Recipient) addresses, and show the print preview (if it is selected), or send the document to your printer, for as many contacts as you have selected. Print preview shows only the first address out of many selected for printing, so you could verify the layout, and then not to be distracted to click Print for each and every address.
To print address labels, you need a label printer, not a conventional laser printer.
Printing labels on a label printer are intended to print a single address (without a return address), commonly due to the small size of print media. Once the setup is done, you can print address labels as follows:
Select one or more contacts from the table, click Print button in the toolbar, and select the Print Address Label for N selected contacts
Next, you will see the selection screen (similar to printing envelopes) where you can verify your selection, and specify the number of copies for each selected address. You can also preview individual labels before you print.
E-Z Contact Book uses a rich text format files as templates:
If for any reason you are unsatisfied with the template for mail envelopes, or you want to change the font, layout, or even add images (a company logo for example), you can edit the file MailEnvelope.rtf the way you like. What you SHOULD NOT DO when editing: change the text of predefined labels (%FROM_ADDR_0%, %TO_ADDR_0%, etc), their number, and vertical order. Also verify if your modified layout complies with your local mailing standards.
Note: be aware that in some cases Windows may still use the original (unedited) version of this file.
Editing templates for mail envelopes and address labels is not recommended.
If you have not specified a Return address while setup option "Print return address" is checked, the program will ask you to do that:
A mailing address is determined as an International one when it has country specified, and the country is different from the Return address country. When the mailing address has no country entered, or both addresses have the same country, it is considered domestic mail, and Country Name will not be printed. If you opt not to print return address, you still have to enter your country name in the "Country for return address" box in the setup screen in order for Country Name to be printed on International addresses.
Formatting rules for the address on an envelope may vary from one country to another. To comply with address formatting rules for most countries, the program provides a number of pre-defined address templates, as well as an editor to create your own address templates, or modify them when needed. To open the editor, click Address Formats button. This will open the following editor window:
In this editor, you can review available address templates, assign them to selected countries or un-assign them. Templates differ from each other in order of data fields, their locations on the address lines. Some fields require to be printed in upper case. Also, address formats in some countries may have double spaces between fields, or comma separators, or, for example, Spain requires the province to be included in brackets.
One address template may be used (assigned) to a number of countries if they share the same format.
All the countries that are not assigned to any specific template will be using the Default address template, which is always present.
You can add a new template, edit an existing one, or delete the one you are not going to use. You can also copy a template into a new one to reduce the amount of editing. You have to modify the copy in order to save it because duplicates are not allowed. Once you have created a new template, you can assign it to a certain country or countries.
Address template editor looks as follows:
See instruction at the top on how to use it. In this editor, you can map available data fields in the desired order. Please be aware of some rules using this editor:
And printed address on an envelope in the corresponding format:
And printed address on an envelope or a label:
References:
Frank's Compulsive Guide to Postal Addresses - The USA
Addressing Guidelines - Canada Post
Royal Mail - how to address your mail
Address formats for Western Europe
Address formats for the rest of the world