How to pass values ​​from another source to the form?

Question

1C-Bitrix

Maybe the wording of the question is not clear.
In the "Ideas" sevris, the form for adding a new "idea" is located at one address /idea/edit/new/ - when the CNC is on, when the CNC is off /idea/?page=post_edit&post_id=new
The form itself contains everything in order to select the necessary parameters, the problem is that in the Category parameter, which you can also select there are a lot of items that you yourself, of course, created. How to open the form for creating a new "idea" with the Category or tag parameter already set. To automatically insert these parameters, you need to change the url to which the transition to the form for submitting these "ideas" takes place.
How to make such a URL (incoming)? What to change in the component code?
In the component code itself, of course, I found those places that are responsible for inserting these values, but how to put transitional values ​​there when coming from an http request, for example, just from a list of news?
Another question is how to use VARIABLE_ALIASES for this?
I would appreciate a quality answer.

Answer 1

If we are talking about the choice of this category in the select,

then it is written right there in the template of this select that if in the get idea = the value of the option from this select, then the value will be automatically put down.
Options value = symbolic category code, lowercase can be specified in get