What is an ISA?
The interest on cash ISA isn't taxed, so you get to keep all the interest you earn. With a stocks and shares ISA, all gains are free from capital gains tax; you don't even need to declare your ISA investments to the tax man.
The beauty of ISAs is that they don’t end when the tax year does. You take it with you into the new tax year meaning each year you get the tax benefits on the cumulative amount. You can keep adding to your ISA and the sooner you do this in the new tax year the more you maximise the tax benefits ISAs give you.

What is the ISA limit?