How to send Json via Ajax?

I know that through "Post to URL", it is clear that simply pasting will not work, because there are symbols "

Preferably an example

I found a solution

I thought that we found the answer, I thought that it is possible to create a file.json, and there is a Request project file action

I selected file.json in the list, but what should I do next?

I searched and did not find it