There are various types of Suites on Holland America ships, depending which ship you choose.
If you go to hollandamerica.com choose "On Board our Ships", then "Staterooms". You will see a list of each on the left-hand side of the page, a descripton, picture and the amenities for each type of Suite.
We have been in Deluxe Suites, which we love and Superior Suites which we also love. The Deluxe Suites are slighty larger with separate dressing room and larger bathroom. On some of the ships, the Deluxe & Superior Suites have double sinks and a bathtub with a separate shower stall. Deluxe Suites have the use of the Neptune Lounge which is like a Concierge Lounge in Hotels.
What ship are you considering? With that information, we could be a little more helpful.
Then of course there the Penthouse Suite which is enormous!