That’s really very quick… you only need to enter the title and that’s it!
A quick add button is available on test cases page below the grid, just click on it and provide the title.
If you have already selected a test suite then your new test case will be automatically added to it.
When a title alone is not sufficient?
You may need to provide more information before the test case can be saved if there are any mandatory custom fields present in the project for test cases.