Chrome Remote Desktop.

Requirements

You need to have the Chrome browser installed and a Google account.

How to use Chrome Remote Desktop

1. Open Chrome, type remotedesktop.google.com/support in the address bar at the top and press Enter.
2. Click the download button under Get Support and follow the instructions on screen to install Chrome Remote Desktop.
3. Click Generate Code under Get Support.
4. Give the code to our customer service – e.g. on the phone or in the chat.
5. When we have entered the code, a box with our email address appears. Click Share to give access.
6. You end the session by clicking Stop Sharing.

See also Google's own guide to Chrome Remote Desktop (opens in a new tab).