You must attend all sessions in your modules that are designated as compulsory.
If you miss a compulsory session, because of illness or whatever, you must must notify the module tutor within six days after the session to explain your absence. Some modules require you to do this by email.
Your course handbook/module outline will identify those sessions that are compulsory.
You will only be asked for proof of you claims if you have already taken unauthorised absences.
If you fail to attend the compulsory session(s) and have not notified the module tutor within six days then you will render null and void all assessment grades in each of the assessment items. A grade of NA will be recorded. You will have failed the module and be required to retake the module or substitute it in a future semester.