Since 2018 it's mandatory for websites targeting European citizens to ask for explicit consent for personal data storing/management. It's regulated by the General Data Protection Regulation (GDPR).
To enable this feature, go to your General Settings area and find the User Content section:
1. Within the site manager dashboard, click on “Settings”
2. Then, at “Settings”, click on “General Settings”
3. Scroll the page and look for the “User Consent” section. To enable this feature, please, check the option “Require user consent to store data”
4. At last, hit “Save changes”