It depends on what you are intending the bowl to be used for. If it's for food it doesn't need to be glossy and the finish should be food safe, e.g. Mahoney's walnut oil.
If it's to stand and admire you have a host of different options: wipe on poly, buff/poly, poly/buff' poly/buff/wax.
There really are so many finishes so you will need to experiment. There are many, many articles on finishing. Do a search on this and other sites.