An individual is an applicant who submits grant applications on their own behalf, not representing an organization, institution or government. Individual applicants are only eligible for grants that are open to individuals and published on the Grants.gov website.
Search for Individual Grant Opportunities: http://www.grants.gov/applicants/find_grant_opportunities.jsp
Individuals wishing to submit a grant application using Grants.gov are required to complete this one time registration process. Neither a Data Universal Number System (DUNS) number nor the Central Contractor Registration (CCR) registration is necessary for Individual Registration.
Take note, if you register as an Individual, you will only be able to apply to grant opportunities that are open to individuals. An individual cannot submit a grant application to a grant opportunity that is open only to organizations.