Google Signals allows better cross-device tracking of users who are logged into their Google account.
How to turn it on:
1) Admin > Property > Data Settings > Data Collection >> Enable Google Signals
2) Click User Data Collection Acknowledgement
Google Signals will enable:
- Cross-platform reports
- Remarketing with Google Analytics
- Ad reporting features
- Demographics and interests
More info about Google Signals: https://support.google.com/analytics/answer/9445345?hl=en