The County of Santa Clara does not issue business licenses. If your business is to be located in an unincorporated area of the county, there is no business license requirement. If it will be located in a city, contact that city directly for business license information.
The County requires zoning and general plan conformance for all uses established in unincorporated areas, including businesses and commercial uses. In those zoning districts where they are allowed, such commercial uses ordinarily require a use permit and/or architecture site approval.
In residential zoning districts, certain low-intensity business activities may be conducted as home occupations. Home occupations are allowed as a matter of right--no permit is required. However, individuals may request County acknowledgment of a home occupation by filing for a home occupation interpretation.
Additional approvals may be required from other governmental agencies (e.g., Department of Environmental Health, State Board of Equalization, etc.) for certain business uses and activities.
If your business is related to the recent legalization of marijuana, please see the FAQ on the subject