Yes, you can transfer a Lifetime ISA from another provider to an AJ Bell Youinvest Lifetime ISA. Transferring from one Lifetime ISA to another doesn't affect your annual payment limit.
As with other types of ISA, you can't make payments into more than one Lifetime ISA in each tax year. So if you've already made payments into another Lifetime ISA this tax year, you'll need to transfer over those payments in full in order to make any payments into your AJ Bell Youinvest Lifetime ISA during this tax year.
For more information read our Transferring into a Lifetime ISA page.