If a minor does create an account, Slack's policy provides for deletion of their data upon discovery, but the burden is on parents or guardians to notify Slack.
Slack collects a wide range of personal data including your messages, files, profile information, location data, and usage patterns, and shares this with service providers, advertising partners, and Salesforce affiliates. While Slack states it does not sell personal data in the traditional sense, it acknowledges that certain data sharing arrangements may qualify as a 'sale' or 'sharing' under California law, which could affect how your data is used for advertising. You can opt out of the sale or sharing of your personal data by visiting Slack's privacy settings or submitting a request at https://slack.com/trust/privacy/privacy-policy.