It is best practice to include a brief descriptive document (often a Readme.txt file) to help others understand your files and data. Below are some examples and tools to help you create such a document.
Metadata is often defined as "data about data" or structured information that describes content and makes it easier to find or use. A metadata record can be embedded in data or stored separately. Any data file in any format can have metadata fields.
A well-known and widely used standard is Dublin Core. However, there are many metadata standards and which one is right for your data will depend on the type, scale, and discipline of your project.
If your field doesn't have a metadata standard or if you require a simpler system, you can record the three most universal types of metadata found in standards: