1. Make sure the customer is able to unsubscribe from your newsletters
2. If someone unsubscribes have a routine where you delete the contact details from the e-mail marketing list
All other matters regarding marketing contacts will be postponed.
If you meet these requirements it is enough for now.
You can look at Triolab.dk for an example how to write the text. https://www.triolab.dk/footer-bottom-menu/cookies/ They also have a good example of legal rights https://www.triolab.dk/footer-bottom-menu/legal-rights/
Grounds for legal processing of personal data
There are six lawful grounds summarised below.
Consent: The data subject has consented to the personal data processing. N.B. In many cases it is not appropriate or even possible to base processing on the data subject's consent. You should therefore always first consider whether you can base the personal data processing on one of the other lawful grounds.
Contract: The data subject has a contract or is to enter into a contract with the data controller.
Weighing of interests: The data controller may process personal data without the data subject's consent if the data controller's interests outweigh those of the data subject and if the processing is necessary for the purpose in question.
Legal obligation: There are laws and rules that oblige the data controller to process certain personal data in its activities.
Not for B2B:
Exercise of official authority or task in the public interest: The data controller must process personal data in order to carry out its duties as an authority or to carry out a task in the public interest.
Fundamental interest: The data controller must process personal data in order to protect a data subject who cannot give their consent, for example if they are unconscious.