In brief
The form of preparation depends on whether the fruit will be eaten alone or will be mixed with other ingredients.
Useful to know
For an orange you'll be using soon, look for a hard fruit that feels heavy for its size. Iowa State describes peeling and splitting into segments, as well as using pieces in salads. This gives different options beyond juicing. [1]
In a fruit salad, choose a size that is easy to take with the rest of the ingredients. For self-serving, the separated segments may be sufficient. It is not necessary for each piece to be shaped like a restaurant decoration.
If the recipe requires juice, consider whether the purchase is for him or the whole meaty part. The two uses are not interchangeable in quantity without specification in the recipe. A strong aroma and a pleasant appearance may be part of the choice, but they do not give a guarantee of equal sweetness to all the fruits in the net.
Sources
For further detail and to check the information: