The most popular types are cash Isas and stocks and shares Isas. Your overall Isa allowance will remain £20,000 however the cash Isa allowance for under 65s will drop to £12,000, intended to encourage investment. You can open an Isa in minutes online, regardless of whether it's a cash Isa or stocks and shares Isa. But check with your provider as some account types can incur penalties, like fixed-term cash Isas or Lifetime Isas. A saver can have an easy access and fixed rate cash Isa, providing flexibility with the certainty of a fixed rate.