In digital communication such as FT8 JT65, software has a function to share information. The shared information is reflected in the PSKR map.
You can see who is receiving you and at what SNR. The other party sends the received information to the host, so you can see the information.
Sharing information is very important.
Setting up the software is very easy. WSJT-X, JTDX check "Enable PSK Reporter Spotting" from Reporting of Setting.
Also, be sure to include your own Grid Locator to ensure that the information is accurate.
Each software has a place to input your own grid locator. Include at least six digits of data. If it is 4 digits, it will become rough position indication. Sometimes it will be on the sea on the PSKR map.
Information sharing is not compulsory. But most people sending their information.