Then go to a reputable nursery and have a discussion with someone there who can help you choose a tree that will grow to the right size for the location you have. Keep in mind that without pruning, even though a tree is called a dwarf, it still may grow to be twelve or fifteen feet high.
Citrus and avocado trees will need at least 8 hours of sun a day and a good source of water. Avocado trees are notoriously messy and like to have the leaves they shed in the late winter left on the ground to act as mulch.
Do your homework to make sure that the time and effort you put into planting a new tree will pay off with lots of rewarding fruit in the years ahead.