GDPR Compliant

I know this is not a new question for the Community, but I still can't find what I am looking for.

As a new business that will need to hold and store client data. Am I safe to use iCloud for this purpose.

If someone could direct me to confirmation from Apple to answer this question, I would be very grateful. Otherwise I am going to have use another provider that can provide written confirmation that data held is secure.

Many Thanks