Archives in the Netherlands are public and accessible for free. The employees are available to ask questions, but they do not do the research for you. Most of them understand English, but it is wise to bring someone along who speak Dutch to interpret the documents for you. Some archives have a genealogical correspondent who will do research for a fee.
The Dutch archives have many old documents. Frequently used documents are available in self service on microfilm or in xerox copies in the study rooms. Other documents are available only as originals. You may be asked to wear cotton gloves to protect the documents.
It’s possible to get a paper copy of most of the documents you see. For the self service microfilms or xerox copies, you can usually make your own copies. Many of the original documents may be photocopied by the employees of the archives. Very old or delicate documents may not be copied but usually you can order photographs of these. The costs of reproductions can vary from archive to archive.