IN WINDOWS 2000 and later versions Microsoft fully supports polytonic Greek. Just install
the Greek polytonic keyboard from the Windows Control Panel.
In Windows XP go to "Regional and Language Options" -> Languages -> Details
-> Add. Please note: when you click the "Add" button, you will see two lists; in the upper one you
select just "Greek", and then at the other list you select the keyboard layout as "Polytonic".
In Windows 7 go to "Region and Language", then to "Keyboards and Languages", and click on the "Change Keyboards" button. At the "General" tab, click "Add" and select Greek, then as keyboard layout "Polytonic".
In Windows 8 go to "Language", then to the "Add a Language" menu, and select "Greek". At the "Options" of Greek select as "Input Method" the "Greek Polytonic".
In Windows 10 go to "Settings", then to "Time & language" > "Region & language" > "Add a language" menu, and select "Greek". At the "Options" of Greek select as "Keyboard" or "Input Method" the "Greek Polytonic".
You can use a Word processor like Microsoft Word, able to handle unicode text. You can also use Outlook Express to write email messages directly in polytonic Greek. You can write in polytonic Greek even in the Notepad. To activate polytonic Greek in a program like Word, press the shortcut key of changing languages (usually alt + shift), or click the flag icon at the bottom right corner of your computer.
Hyphenation
Office 2013 hyphenates polytonic Greek just fine. For older versions you can download
Ancient Greek Hyphenator for Word 2000/XP. It is a free template that
adds hyphenation macros to MS Word (screenshot). I have tried it in a long document (900
pages) written in polytonic (ancient and modern) Greek, and it worked
without faults and very fast.
A help file is also included in the
installation (zip) package, but there should be a warning about Word
Index.
If you have an index in your document, after hyphenation all those index entries
that 'touch' a word which can be hyphenated, will be lost; you must
place index entries to touch a punctuation mark or a small word, a
word that will not be hyphenated, like an article. Punctuation marks
and empty spaces save the index entries. Experiment with index entries in
a selected text before you hyphenate the whole document.
Apple
supports unicode, and there are Greek polytonic unicode fonts for Mac
to download. Read more at Sam
Tucker's page, where you will find instructions and links to fonts
supporting polytonic Greek
You can use a Word processor like Microsoft Word, able to handle unicode text. You can also use Outlook Express to write email messages directly in polytonic Greek. You can write in polytonic Greek even in the Notepad. To activate polytonic Greek in a program like Word, press the shortcut key of changing languages (usually alt + shift), or click the flag icon at the bottom right corner of your computer.
You can view a page with 
