Your Account Number and Sort Code are used to identify your account.
The Account number is personal to you and identifies your account, whilst the sort code identifies the operator of your account (in this case, Suits Me).
They're used in money transfers, if an employer, friend or family member wants to transfer you money you need to give them your account number and sort code which tells their provider where to send the money to.
You can find them on your online money account, through the mobile app or on the back of your debit card.