If a template has been certified for employees to complete certain fields eg an invitation to a meeting in the UK where date, venue etc needs to be added, does the final form of each invitation need to be certified prior to issue?

If a company provides a list of approved venues, and the only other information to be added is a date then it is likely to be acceptable not to certify the final form of each invitation. If, however, the agenda can be amended this could require further examination or even certification, depending on the wording added.