To set identical headers for all requests in a Postman Collection, you can use pre-request scripts. Follow these steps:
Right-click on the Collection to access the pre-request tab.
Add the lines of code below to the pre-request scripts section to add the desired request header for all requests in the Collection:
pm.request.headers.add({ key: 'TestHeader', value: 'testValue' });
Click Update to save the script.
Run any request within the Collection, and you can check the Postman console to verify that the headers have been added successfully.
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