Privacy policy of the website owner

My scenario is the following: Clients of the web give their data to the owner of the web -I do the maintenance and the total management of the server where the web is (therefore I could have access to the data of the clients of the owner of the web) -I rent servers to a hosting company (this could access the data of those customers too).

Answer:

Form your description it looks like you are acting as a data processor on behalf of the website owner which is the data controller. This means that the date controller would need to mention in its website Privacy Notice that personal data of the visitor may be transferred to third parties (is not necessary to mention by name which are those third parties) .

To learn more about privacy notices check out or webinar “Privacy Notices Under the EU GDPR” (https://advisera.com/eugdpracademy/webinar/privacy-notices-under-the-eu-gdpr-free-webinar-on-demand/)