The Show Exam Disclaimer System Configuration setting determines whether participants are shown a disclaimer message which they must acknowledge before they can start exams.
You can change the default text in disclaimer, but not directly in the LMS application. Instead you can add the msg.exam_disclaimer.content label key to your custom.properties file on the LMS server and set its value to what you want your message to be.
You can include the following parameters in disclaimer messages, so that you can include dynamic and targeted text:
The default disclaimer (configured in standard.properties) is I confirm I am {0}, {1} and I want to launch {2}.