Dublin Core (DC) is a metadata standard that is designed to describe resources, the standard includes two levels Simple and Qualified, this is a good resource for more details on the DC standard and its history:

https://www.dublincore.org/specifications/dublin-core/usageguide/

Starter Edition supports simple Dublin Core which has the following elements, none of these elements are mandatory and you can choose to use as few or as many as you require:

Title: The name given to the resource. Typically, a Title will be a name by which the resource is formally known.

Description: An account of the content of the resource. Description may include but is not limited to: an abstract, table of contents, reference to a graphical representation of content or a free-text account of the content.

Subject: The topic of the content of the resource. Typically, a Subject will be expressed as keywords or key phrases or classification codes that describe the topic of the resource. Recommended best practice is to select a value from a controlled vocabulary or formal classification scheme

Creator: An entity primarily responsible for making the content of the resource. Examples of a Creator include a person, an organization, or a service. Typically the name of the Creator should be used to indicate the entity.

Publisher: The entity responsible for making the resource available. Examples of a Publisher include a person, an organization, or a service. Typically, the name of a Publisher should be used to indicate the entity.

Contributor: An entity responsible for making contributions to the content of the resource. Examples of a Contributor include a person, an organization or a service. Typically, the name of a Contributor should be used to indicate the entity.

Date: A date associated with an event in the life cycle of the resource. Typically, Date will be associated with the creation or availability of the resource.

Type: The nature or genre of the content of the resource. Type includes terms describing general categories, functions, genres, or aggregation levels for content

Format: The physical or digital manifestation of the resource. Typically, Format may include the media-type or dimensions of the resource.

Identifier: An unambiguous reference to the resource within a given context. Recommended best practice is to identify the resource by means of a string or number conforming to a formal identification system.

Source: A Reference to a resource from which the present resource is derived.

Language: A language of the intellectual content of the resource.

Relation: A reference to a related resource.

Coverage: The extent or scope of the content of the resource. Coverage will typically include spatial location (a place name or geographic co-ordinates), temporal period (a period label, date, or date range) or jurisdiction (such as a named administrative entity).

Rights: Information about rights held in and over the resource. Typically a Rights element will contain a rights management statement for the resource, or reference a service providing such information