context in selected area o current cursor position

[proidit]

sorry i'm learning.
How can i limit the context to only the selected text in the code (example "convert the for loop of the selected area to foreach") or limit it to the cursor position in the code (example "print hello world at the current cursor position")?
If I select the area and use the "add to context" function it does not respect the request and acts outside the selected area and even in other files!