Email addresses, names, preferences, IP records and campaign activity can all be personal data. A responsible email program knows why each field is collected, who can access it and when it should be corrected or removed.
Extra fields create extra responsibility. Do not request a birth date, phone number or postal address simply because the form builder makes those fields available.
Store the signup source, date and version of the language shown at the time. A database entry saying only "subscribed" may not explain what the person agreed to receive.
Limit account permissions to people who need subscriber data. Protect exported files, avoid leaving copies in shared folders and remove temporary files after their purpose is complete.
Document how requests are verified and completed. Deletion should also account for exports and connected systems while preserving only records that must be retained for a legitimate reason.
Before choosing a platform, understand where data is processed, which subprocessors are involved, how backups are handled and whether the service provides the controls needed for applicable privacy obligations.