HTTP(S) Load Test may require you to use some variable data that will be used while testing your URL.
For example, you can test different types of form submit such as registration forms, advanced search form, filter forms, etc. by simulating an HTTP(S) request with dynamic parameters. To accomplish this you need to set up Context Parameters for the request and provide a list of dynamic values for these parameters in the test scenario. You can set up context parameters for the URL, Headers, request body, and for the custom script in the Prepare script field.
To set up context parameters for the test, see How to Use Context Parameters in HTTP(s) Requests.
When the test task has been created and saved, you can specify the list of Dynamic Variables (Context Parameters values) in the test scenario. See Uploading Dynamic Variables to the Test Scenario for more details.