Programme preferences will be mandatory for applicants to complete in order to receive an offer.
It is yet to be decided if regions will give a choice of programmes and the level of which applicants will be able to choose (eg just the region or different sectors within that region). This will not be possible to confirm until programme preferences are open and may vary between region as to the level of detail given.
Even if there is just one choice, applicants must preference the lone option in order to be considered at the offer stage.
Much of the guidance on programme preferences for those applying to IMY1 is applicable to IMY3 so go there for more information.