Apple and Google have been working to build a platform that will trun everyone;s smartphone into a tool for tracking COVID-19.
By using bluetooth, the contract tracing software will detect other smartphones and alert you if they have been in contact with someone who tested positive.
This update will be pushed to peoples smartphones automatically.
There are some obstacles they need to overcome, things like minimizing false positives, and since bluetooth can send signals through walls, people may be notified even when they have not been in actual contact.
To protect anonymity the alert will not be in real time
This is how they think it will work
This is what it will look like on your phone