General stylistic and accessibility practice information is available on https://wiki.albany.edu/x/gy8sAQ
To find the service tag or serial number for your Dell or Apple computer, follow the instructions below.
The service tag is usually on a sticker on the computer
For a laptop, turn it over on a flat surface to see the bottom
For a desktop, look on the side or top of the tower
Dell also has further instructions available.
The serial number is usually engraved in small text on the bottom of the computer near regulatory text.
For a MacBook, turn it over on a flat surface to see the bottom
For an iMac, lay it down on a flat surface to see the bottom of the foot/base
Apple also has further instructions available.