Single person company becoming ISO 9001?

First, note this is typical corporate culture, apply one size to fit all rules.
Second, there is no basic or entry-level ISO, but ISO 9001:2015 is very flexible. Organizations can design a very light quality management system. For a single person company, you can minimize documentation to almost only what is mandatory.

You can find more information in the following links:

• List of mandatory documents required by ISO 9001:2015 - https://advisera.com/9001academy/knowledgebase/list-of-mandatory-documents-required-by-iso-90012015/
• Should you use a gap analysis in your ISO 9001 implementation? -https://advisera.com/9001academy/17/use-gap-analysis-iso-9001-implementation/
• Free ISO 9001:2015 Gap Analysis Tool -https://advisera.com/9001academy/iso-9001-gap-analysis-tool/
• Checklist of ISO 9001 implementation & certification steps - https://advisera.com/9001academy/knowledgebase/checklist-of-iso-9001-implementation-certification-steps/
• Enroll for a free course - ISO 9001:2015 Foundations Course - https://advisera.com/training/iso-9001-foundations-course/