Sometimes you if you have an issue related to a Web application you will be requested to share the HAR file which contains information about the problem.
In order to retrieve the HAR file, please perform the following points:
Open developer tools using F12 on the keyboard.
Navigate to the Network tab
Clear table content
Perform your desired action (Make sure the error you encountered happened)
Right-click on one of the table rows
Click 'Save all as HAR with content' and send the saved file to the team
Make sure to record the error you have encountered, if the error is not recorded in the network tab the HAR file will not contain the relevant information needed to resolve your issue.