How do I delete a print job from my ipad

For iPadOS 17 and earlier, if a printing job is pending, the Print Centre is accessed using the App Switcher page. To expose the App Switcher page, swipe-upwards from the bottom edge to the centre of the screen, pausing briefly before lifting your finger from the screen; select the Print Centre thumbnail.

For iPadOS 18.x, the Print Centre is now accessed from the Control Centre - although you will likely need to add the associated control from iPad settings. The Control Centre is exposed with a downward-swipe from the top-right corner of the screen:

Customisation of the Control Centre, including adding and arranging control icons, is fully described within the iPad User Guide:

Use and customize Control Center on iPad - Apple Support