Answer by Miro for Is there a way to permanently set the font and window size in PuTTY?

Actually it's very simple:

1. click on 'Session', Load desired one (click on "LOAD" button)
2. click on 'Window', adjust then desired values within 'Appearance', 'Colours',..
3. click again on 'Session', and click on "SAVE" button!

It's ready! Values are saved to your desired session.

If want to do this as permanent for the - Default session, click on it and do the above. Each saved session should be adjust separately!

BR,Miro