When you sign up to be on my mailing list your email address is stored with the provider Mailchimp. I have access to your email address but will not pass it on to anybody, unless there is some over-riding legal reason to do so.
Everyone who signs up does so consensually having gone through a double opt-in process. All newsletter emails have an opt out button and you can opt out at any time. I only collect the bare minimum of information, i.e. your email address
As the mailing list grows it is likely that the list I hold will be segmented in order that I can direct material to people that have the most interest in it. For example, some people may be interested in online tuition and other may not so I would have a separate segment for each group. This is gathered from your responses to mailouts and stored on the email provider’s system. Once again I will never pass this information on. My provider is Mailchimp who are rigorously compliant with GDPR, so your data is also safe with them