In your study Information Technology in key stage 3, you can learn how to use computers to do everyday things and you can learn something about how things work (ICT) - computer hardware, software and networks. And you can study computer science - essentially, programming.
There is recently more opportunity to study computer science at GCSE level with the addition of new computer science exam specifications that afford students a better knowledge and understanding of IT as it occurs in the world, and a range of skills better suited to working in IT.
In Year 7 it's likely you will begin with creating presentations in Powerpoint, and go on to explore spreadsheets in Excel1. You will begin to consider databases and do some programming, perhaps using Scratch. Then, throughout Key Stage 3 and toward GCSE, you will develop your skill using these different applications and also explore image editing and web page creation. Your programming will likely progress to using python, or a similar text-based language, and perhaps Flash. Later, you will learn more about how computers work, investigating boolean logic, binary and the components of a computer and a network.
Modern applications are, of course, GUI-based2 and you can quickly learn how to use them and get things done. Mastering their use, however, takes a bit longer. Typically there are many facilities that are not so easily discovered and besides, as you further practice your skills, your work with them can produce more professional results - well presented, reliable and suited to the purpose you had in mind.
These kinds of applications are used everywhere in the modern world. A person working for a large firm needing to give a presentation will likely use presentation software and will want to make sure of a number of things: that the presentation will run smoothly and help them get their point across; that the visual aids promote understanding; and that the presentation is consistent with the company's colours and ethos. Digital presentations are also commonly used for information and instruction - they can be run by the recipient and perhaps include some user interaction. Digital presentations are used in a public setting for just this kind of purpose especially in conjuction with a touch-screen. The use of documents is by no means outdated. Organisations continue to use printable documents, the most common among these being Microsoft Word1 documents and PDFs. Also, if you are going on to further and/or higher education, you will find yourself often using typed documents in your assignments. Spreadsheets are very widely used in businesses of all sizes, especially Excel spreadsheets. It is not unusual in small businesses for the whole of office management to revolve around the use of spreadsheets.
Relational database, too, is ubiquitous. Any business or organisation bigger than a sole-trader is likely to use a relational database of some kind2. Just as a presentation, for example, is created for a particular purpose, so too a database is created by someone to perform in a particular way. An important aspect of database is that the data must be kept safe and secure - any organisation will go to some length to make sure that their data cannot be accessed illegally. Often it is our data that is at stake, especially in large organisations. In school you will likely use Access3 which is still used in the form you may be familiar with by many smaller companies. The internet can also be thought of as a kind of database in which information can be retrieved using a system of IP addressing and in which access to data is controlled by means of server applications.
Anything you produce using these applications, because of the work involved in making your solution work in a particular way, can be thought of as an application in its own right, albeit one that depends on its host application to run - Powerpoint or Word or Excel etc. Especially if you write a database this should properly be considered an application. And then there are stand alone applications such as a python program which you will run using the python interpreter but which has the potential of being compiled to run anywhere on windows or OS X or linux. Or a website which runs in any web browser.
Software modelling of real-world problems - spreadsheet modelling, micro-computer controlled robots, simulation software like Flowol.
Understand computational algorithms such as search and sort.
Understanding boolean logic - AND, OR, and NOT for example, and its use in circuits and programming.
Understanding binary numbers and arithmetic.
Write in 2 or more programming languages including a text-based language using, for example, lists or arrays and using procedures or functions.
Understand the hardware and software components of a system.
Understand how instructions are stored and executed and how data of different types is represented and manipulated using binary digits.
Develop solutions using and combining multiple applications with attention to fitness to purpose, reliability and suitability.
Understand responsible and safe use of IT including ways of working to protect identity and privacy online.
Not a complete list.