It is decided by your own preference. For bifocal glasses, you need time to get used to them, because they have two centers with the upper part to see the far distance, with the lower part to see the near distance. For two seperate general wear, you have to change between those two pairs, it is not so convenient.
You'd better go to your eye doctor to have an eye exam to see whether you need glasses for distance and reading. Maybe you only have to wear reading glasses. If you do need glasses for both distance and reading, then bifocal glasses is a good choice.