Short answer
HubSpot's KB: the company Industry property has about 150 pre-defined options. They can't be deleted, but you can add custom options. If you need a short, controlled list, a custom dropdown is cleaner.
1. The property
Company properties in my demo portal: Industry is a dropdown in Company information.

2. Enrichment
Enrichment can fill Industry. See enrichment settings.
3. Related
Option labels vs internal names.