For body copy, I most commonly recommend Verdana. Arial is also a good, legible choice.
For headlines, you can stick with Verdana or Arial â€“ but donâ€™t mix and match these together. For example, donâ€™t use body copy in Verdana and then headlines in Arial, because it will look like the text used for the headline is too â€œskinnyâ€.
Or, if youâ€™d like to add some variety, you can go with a serif font for the headlines and subheads. Two of the best serif fonts to read online are Georgia and Times.