GDPR applies to individuals as well as companies if they provide services to customers within the EU/EEA[0], as long as they are either a data controller or data processor, which are explained better than I can in the source below[1].
If the business is based in the US, things get a bit more complicated due to the CLOUD Act[2].
https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELE...