Why it matters: It is essential to inform users whether their action was successfully performed or not. For example, after submitting a form, a clear confirmation message (it can be a colour banner) will demonstrate that users can proceed to the next task.

How to test it: Check all places where users need to fill in the information. After the input is complete, check whether it is displayed that action was successful or not. Make sure that feedback is clear regarding the end status.

Check these two examples**:**