Your exam vouchers will be issued to you shortly after purchase. They will be valid for 12 months and you will need to schedule your exam session in this time.
If your course or Managing Professional Program is extended beyond 12 months, the extension price will include a 6 month extension to your exam voucher(s).
There are very strict examination scheme rules and it is your responsibility to ensure that you comply with them. For all ITIL 4 Specialist / Strategist exams you MUST hold the ITIL 4 Foundation Certificate and have relevant proof of course completion.