Typography: Purpose of Type
To be able to determine which type to use you have to first remember the reason why you need to choose an appropriate type. The very basic purpose of font types is to draw attention to the text. That being said the font type should be chosen so as to present the text best making sure it doesn’t fade into the background but at the same time making sure that it does not overpower the text. This means no ornate letters and no screaming colours.
Another important thing to remember is that it exists to make the text readable. This means that you should never choosy a pretty or cool text if it is hard to read. Spacing between letters and lines comes into consideration as well because even if the type used has clean lines tightly packed letters are harder to reader. This also implies using the appropriate font size. If your target audience are older you should use bigger font sizes regardless of the typeface you use.