Here you will find the letter.

Explanation:

Every person who is registered with the tax office has an administrationnumber, the so called sofinumber. A sofinumber is only provided once. The tax office sends you now your child's sofinumber.

The sofinumber is not only needed for work but also necessary for other organisations like schools and banks. That's the reason your child needs a sofinumber.

The letter mentions the personal details from your child. Please check these details. If the information is wrong please adjust it and send the letter back to the taxoffice.