Structured directory citation
A business profile on a directory may display the business name, address, phone number, website, hours, categories, description, photos, and review information in fixed fields.
Niche citation
A professional or industry directory can function as a citation when it lists the business or practitioner together with relevant identifying information.
Unstructured mention
A chamber-of-commerce article, event page, sponsorship announcement, local news story, or association page may mention a business naturally in prose. That can still function as a citation even without directory fields.
What is not useful
Creating irrelevant profiles solely to inflate a citation count is not the same thing as building a useful local presence. Prefer credible, relevant, and geographically or professionally appropriate sources.