From the income year in which you reach the age of 17 onwards, you will be treated as an independent taxpayer. You must assess your taxable income and capital on your tax return. When you are assessed independently, this means that you will be liable for the tax.
You will be sent your own tax return with information on the incomes and capital amounts that you must check. This information will be reported by your employer, bank, etc. If the precompleted tax return is correct, you can use what is known as the submission exemption arrangement, which means that, by not actively submitting the tax return, you passively accept that the tax return is correct and complete, without having to do anything.
You must submit the tax return if you make any changes.