A stocks and shares ISA can be used to put your money in a wide range of investment products.  You won't pay tax on any investment growth or interest earned in the ISA.  A stocks and shares ISA is a higher risk than a cash ISA - you could lose a large portion, or in extreme cases, all of the money you invest.  On the plus side, there is greater potential for earning more money in a stocks and shares ISA.

A stocks and shares ISA can include:

• Stocks and shares in companies.
• Unit trusts and investment trusts.
• Corporate and government bonds.
• Open Ended Investment Companies (OEICs).
• Exchange-traded funds (ETFs).

These are all discussed in more detail in the Stock Market section.

Key factors for a stocks and shares ISA are:

• Higher risk.  The value of your cash ISA will never drop (unless you withdraw the money), and you will be guaranteed to receive the amount of interest the account provides (be it fixed, variable or a tracker rate).  With a stocks and shares ISA, the value of your investments can go up and down significantly on a daily basis.
• Where to open an account.  You can open a stocks and shares ISA with a bank or building society, but they are cheaper to do through an investment platform - an online service that allows you to buy and hold shares, bonds and funds in one place.  Examples of such platforms are IG and AJ Bell.   
• Opening balance.  The minimum amounts vary across providers.  
• Fees and costs.  Consider the costs associated with buying stocks and shares and investing in funds - this will be made clear on the providers website.  As an example, if you buy UK shares on IG, you will pay 0.5% stamp duty (see below) and an £8 dealing charge (set rate for IG if you don't trade often).  To buy £1000 worth of shares would cost you £13 (£5 stamp duty and an £8 dealing charge).  To sell them will cost you another £8, so if you sold the shares for the same price you bought them, you would have £21 less than you started with.  You also have to pay a fee for the platform holding your investments - some charge a set rate (such as £24 per quarter with IG if you make no transactions in that quarter) or take a percentage of your investments (for example, 0.5% with AJ Bell).  You can see how the charges add up!  The dealing charge for investing in funds is normally less than shares, but check the conditions of the providers you are interested in.
• Stamp duty reserve tax (SDRT).  When you buy most UK shares online, you will pay a 0.5% tax. It doesn't apply when you buy unit trusts, mutual funds, ETFs or OEICS (more on all of these to follow), or for shares listed on London's Alternative Investment Market (AIM).  It does apply when you by into a UK investment trust, however.  The majority of investment platforms you use will make the charge clear to you, add it to the cost of your investment and pay it to HM Revenue and Customs (HMRC).
• Investing for the long term.  Historically, in the long run, stocks and shares (and the funds, trusts etc) you can use to invest in the stock market have outperformed money in cash savings accounts, but there is no guarantee they will in the future.  In times of volatility, you can see significant fluctuations in the value of your investments on a daily basis.  Investing over a time period of at least five years will help your investments ride out the market fluctuations.
• Protection scheme.  Ensure your stocks and shares ISAs is protected by the Financial Service Compensation Scheme (FSCS).  There's an important distinction between the protection that is offered with a cash ISA.  The £85,000 of protection is protecting you against the provider of the ISA, not the companies or funds you have invested in.  For example, if you have £25,000 of investments held with an Acne Investments Inc (made up name) and they go bust, your £25,000 is protected.  If you had bought £25,000 of shares in Acne Investments Inc and they went bust, your shares aren't protected.
• ISA transfers in and out.  Applicable if you are moving money from another ISA - ensure the new provider accepts transfers from your existing cash ISA or stocks and shares ISA.  Be aware, you may have to pay exit fees.

What I have done.  I opened a stocks and shares ISA in 2014 with the help of a qualified Financial Advisor throughout the life of the account.  The Financial Advisor selected funds for me to invest in.  We spoke regularly and he advised me whenever I had money to make further investments.  I paid an annual charge of 0.5% for his services (in addition to the fees I paid for the platform and funds), but his knowledge and expertise was absolutely worth the 0.5% fee.  In the 8 years I had the ISA open, the return averaged at 8% a year, far more than I would have received in a savings account, or if I had picked my own investments.  I moved the money to a cash ISA in 2022 due to the volatility of the stock market at the time - I wanted a lower risk option and accepted that this would mean a lower (but guaranteed!) return.  However, I recently opened a stocks and shares ISA to get money back into stocks and shares.  I've learned a lot about the stock market and investment products in the past few years, so I am more confident in selecting the appropriate areas to invest.