This is for the purpose of defining 'Term', at the end of which there will be an option to extend subject to certain conditions set out in the agreement.
Note it is likely that the Supplier will wish to end this agreement to coincide with a financial reporting cycle, in which case that date should be inserted eg. 30 June 20__, 31 December 20__.
This is preferable to inserting '6 months from the date of this Agreement' which may prove difficult to fit with fiscal reports.