Supporters' loyalty will be rewarded with those who regularly attended games during the Euro qualifying campaign to be given priority.
The decision follows discussions this week between the Irish FA and Uefa.
Priority will be given to block bookers who renewed tickets after the 2014 World Cup campaign and those who bought tickets for Euro 2016 qualifiers.
The success of applications from fans who apply for two tickets will be affected by the "purchasing behaviour" of the second named applicant, according to the IFA.
"Supporters who apply for one ticket will have a level of priority based on their own purchases, while fans who apply for two tickets will have a shared priority allocation," stated the IFA's head of communications, Neil Brittain.
"If a block booker who applies with another block booker, then both remain at the level of priority that they would have had if they had been applying as individuals.
"However, if a block booker applies with a supporter who hasn't attended any Northern Ireland games in recent years, then the priority points will be divided between both."
The move to allow fans to apply for two tickets is good news for Under-18s, who would not have been able to purchase tickets under Uefa rules.
The IFA has over 500 junior campaign card holders who are now eligible to apply for tickets.
Northern Ireland fans will be allowed to apply for two tickets to the Euro 2016 finals in France.