They are called Individual Savings Accounts or ISAs. ISAs are a place where you can put a range of savings and investments. However, you don't pay any tax on the interest or income you earn. There are two types of ISA: 1  a cash ISA. 2  an investment ISA.3  Investment ISAs are also known as stocks and shares ISAs.SAs are a place where you can put a range of savings and investments. However, you don't pay any tax on the interest or income you earn. There are two types of ISA: 1  a cash ISA. 2  an investment ISA.