It is recommended that you have these numbers to hand when contacting PlayStation Support. 

If attached, remove the base to reveal the PS5 serial and model numbers.

• The serial number is comprised of a long series of numbers and is located on the bottom of the console when positioned vertically.
• The model number consists of the letters CFI, followed by a series of numbers and a letter. The model number is located on the bottom of the console when positioned vertically.