Currently working on a user registration form. And in my backend server, I build this JSON format API to take the data in the user_data field and profile_data field. So, if we pass the data in this particular format then it will store the given information. So, how to pass the values in this format using fetch and JSON.stringify.

so, the above image is just an example of how to pass the value if the JSON looks like this:-

So, I want know how to pass the value if the API JSON has multiple keys and also those have multiple values.