Rich Dad, Poor Dad

It's by no means a great book, but it covers the basics, it's accessible, and I read it at just about the right time around 18 years of age.

Something better / more modern might be:

https://www.penguinrandomhouse.com/books/317640/the-index-ca...

Learning the basics of accounting goes a long way too.

Unfortunately, you also need to read up a little bit on the gory details of taxes and deductions, pension schemes, etc in your country, and that stuff changes all the time, so the books and knowledge rapidly gets out of date - you want to try not to get distracted by the minutiae of that, and focus on accounting, assets and liabilities, income and expenses.