Sure, in small amounts. They shouldn't make up so much of the diet that other things go lacking, but a little fruit can offer some extra nutrition. But NO grapes or raisins. These can be toxic to dogs in much quantity.
Mine like bananas, blueberries, strawberries, peaches, apples...
As treats, you can just feed a bite of raw fruit. But dogs can't digest plant-based foods very well, so mashing, cooking, or freezing any fruits or vegetables will make it a bit more nutritious.
If you like the idea of feeding "people food" to your pup, also consider feeding him little bites of other things--especially meat, fish, cheese, eggs, yogurt, cooked vegetables--all of these things can be interesting treats or mix-ins for his food. I'm not a big fan of feeding dogs much (if any) starch (bread, pasta, potatoes, corn, etc.)