Hi! @Cookie0621, Welcome to HP forums.
I understand you need to know how to disable the auto-detect feature on your printer.
Don't worry I will try to help you out.
Unfortunately, you cannot print on an "undefined" paper size without printers. While the feature is available in word, our printers only recognize the main paper sizes (these change depending on the country sometimes).
The reason for this is because non-defined paper sizes open the printer and the print job to a number of risks including paper jams or misaligned printing. This is why the feature is no longer on HP printers.
However, you can override it by changing the settings to manual.
Change the paper settings to custom paper size and change the dimension accordingly save the settings and check if it helps.
Hope this answers your query!
Have a great day ahead! 🙂
A4Apollo
I am an HP Employee