Front: user's name, telephone number, postal code, area code, address (accurate to the house number), store of purchase, installation unit, outlet code, purchase date, installation date, installer, service supervision card number, etc. Don't fill in the rest, remember to stamp the official seal when you hand it in.

Anyway, everything should be filled in, the user's signature is the most important, and the date (this date must be consistent with the previous installation date). If it is a frequency converter, you need to let the user fill in the words "vacuumized" in the space above the user's signature.