In order to open a Lifetime ISA, you'll need to meet certain eligibility criteria.
You must:
Be aged 18-39 (you need to open and fund the account before you turn 40)
Be a UK resident
Not have exceeded your £20,000 ISA limit in the current tax year
If you're using the LISA to buy a home, you must be a first-time buyer
Once your account is open, you can pay into it every year until you reach 50. From that point onwards, you can't add any further funds, but you'll continue to generate interest or investment gains.