As mentioned above, it depends on tradition and personal preference. If this is YOUR altar, for your solitary practice, you may do whatever feels right to you.
Having said that, the direction or quarter you face can dictate the energy of the work you’ll be doing.
So if you follow the Western tradition, for example, an altar facing West will be ideal for bringing the emotional essence of Water to your ritual; if it’s facing South it will be infused with Fiery passion; if it faces North it will be grounded by Earth, and if it faces East it will channel the wisdom and ideals of Air.
That’s just one idea. It shouldn’t be taken as dogma. And there are other possible associations as well (e.g. if you live in the Southern hemisphere you may use a different approach).
There are some more ideas in this forum topic: Directionally challenged