To use Connect, install the Connect software on your Raspberry Pi. Then visit connect.raspberrypi.com to access your Raspberry Pi via screen sharing in a browser window. You can use the desktop as if you had plugged a monitor into your Raspberry Pi.

Connect uses a secure, encrypted connection. By default, Connect communicates directly between your Raspberry Pi and your browser. However, when Connect can’t establish a direct connection between your Raspberry Pi and your browser, we use a relay server in London. In such cases, Raspberry Pi only retains the metadata required to operate Connect.

https://www.raspberrypi.com/documentation/services/connect.html