Absolutely, you can use your Help to Buy ISA with a Generation Home mortgage.
A Help to Buy ISA is a type of Independent Savings Account. The government will top up your savings by contributing 25% of your total, providing you don't exceed the set limits.
Applications for the Help to Buy ISA closed on 30th November 2019, but if you had an account by then, you can contribute to it until 2029.
Find out more about the Help to Buy ISA here.