GDPR (General Data Protection Regulation) is a legal regulation in European Union law that aims at giving EU citizens more control over their data.  Sending emails and storing your prospects’ data in CRM is related to processing personal data.  One of the cases when processing personal data is considered legal — when the «processing is necessary for the purposes of the legitimate interests pursued by the controller» (Article 6). The controller is the company that sends the email, i.e., you. Recital 47 provides more detailed explanations about legitimate interests. It states that: «The processing of personal data for direct marketing purposes may be regarded as carried out for a legitimate interest.» «At any rate, the existence of a legitimate interest would need careful assessment including whether a data subject can reasonably expect at the time and in the context of the collection of the personal data that processing for that purpose may take place.» Even so, the recipient has the right to ask you to stop processing their data. Suggestion: add an unsubscribe link to your mail.