You can name as many executors as you like in your will, though the maximum number who can apply for probate to administer your estate is four. It makes sense to have at least two or three, in case any of them pre-decease you or later decide they do not want to (or cannot) act as an executor.
It's common to ask friends or family to be executors. It makes sense to choose individuals who are good at administration, have a bit of financial sense, and are trustworthy. You may also want to consider naming a professional executor like Estate Planning Solutions and Kings Court Trust.