>I’m getting an error

of course you do. your syntax is wrong (it even tells you where the issue is)
https://www.w3schools.com/jsref/jsref_regexp_test.asp

it’s not a plugin (well, it is kind of , but it’s inbuilt so to speak)
it’s simply a way to add a custom validation rule you will then have available in the validation dropdown in wppizza->order form settings for whatever field you want to apply this to
i.e

//to add your own rule - let's say 'my_rule'
add_filter('wppizza_filter_validation_rules','my_function');
function my_function($validation_rules){
$validation_rules['my_rule']= array( 'lbl'=> 'My Rule', 'parameters'=>false, 'callback'=>false, 'enabled'=>true);
return $validation_rules;
}

will add a “My Rule” to the dropdown

$.validator.methods.my_rule = function (value, element) {
return this.optional(element) || /^(?:\d+|\d{1,3}(?:[\s\.,]\d{3})+)(?:[\.,]\d+)?$/.test(value);
}

is the javascript that validates the field that has “My Rule” as validation selected (i.e it should return true or false depending on how you want to validate this)

and if the concept of filters/actions s new to you:
https://docs.wp-pizza.com/developers/?section=filters-actions-functions

the order history shows the information that was sent in the email to the shop (i.e the info in the email to the shop == info in order history )

if you want data to be available in the emails (for example) you’ll have to add a/that checkbox to the main formfields instead before going to the confirmation page.

the confirmation page checkboxes are there to – for example – stop people submitting an order unless they have accepted the T&C’s (or similar) if it was made required (or whatever else you want to do with the options there)

at some point in the future probably, but there are no immediate plans for this at the moment I’m afraid

if you set to display your default text when no selection has been made yet, then that’s what it does and should do.

presumably your text says “as soon as possible” so 11:30 is as soon as possible

you must speak to your printer manufacturer / read their manual as to how to enable borderless/nomargin by default

depending on how your printer handles it though, you could try to use the/a html print template and set the with in th ecss from 100% to some absolute value (i.e 2in for example or 70mm or whatever size is appropriate)
might or might not work.just an idea. depends on printer or whether margins are automatically added by something

i’ll see what i can reproduce here
might be a conflict between the postcode and preorder plugin (because when i simply do not select any postcode in the popup it DOES say “as soon as possible” …)

will get back to you when i know more. this might take a bit

PS: i actually have an idea what might cause this and it’s not a conflict as such but something in the preorder plugin itself (that’s my current thought at least … i won’t bore you with the details )

>If I deactivate the plugin, there is no time to choose, also the text “as fast as possible” is not visible.
i’m not with you. if you de-activate that plugin it doesn’t do anything . of course there should be no text and nothing to choose from (I really dont understand the confusion there)

>No matter if the shop is open or not.
of course. that’s the idea of the plugin
you can order when the shop is closed for the time when the shop is open

for the rest i cannot say much without at least a link.