Hi there!

Thanks for conatcting us.

This form is coming from a module, here is a screenshot: https://prnt.sc/ZbRio5a0OFTc

You can turn off the "Enable room quantity" in the module settings as follows: https://prnt.sc/MfOHuxhRQqzD but it will remove all three off them and will look like this: https://prnt.sc/3cZ-kcl7lfmJ

If you want to show the adults field too then you need to customize the codes.

Note: Code customization support is prohibited here.

Best Regards