It is possible to transfer your Help to Buy ISA in part or in full.
If you transfer the value of your Help to Buy ISA as it was on 5 April 2017 before 5 April 2018 it will not count towards your Lifetime ISA payment limit of £4,000 and the full amount will qualify for the government bonus. If you just want to transfer this amount simply tick this option on the transfer form and let us know the approximate value of your Help to Buy ISA. If you've already paid in £4,000 to your Lifetime ISA this year you'll need to use this option.
You can transfer another partial amount of your Help to Buy ISA at any time, but remember you can only use either your Help to Buy ISA or your Lifetime ISA towards buying your first home. You'll need to let us know on your transfer form how the value is split between the period up to and including 5 April 2017 and the period after this date. The value that is from before 5 April 2017 won't count towards your LISA £4,000 payment limit if it is transferred on or before 5 April 2018, but the value from any subscriptions (plus interest) made on or after 6 April 2017 will. So you'll need to make sure you have enough of your annual payment limit left to transfer this into your Lifetime ISA.
However the money is transferred to your Lifetime ISA it will qualify for the government bonus.