Good day! Faced such a problem on Delphi 7.
Here is a piece of code:

procedure tform1.button1click (Sender: Togject);
Var Fileonnet, LocalFileName: String;
 Begin.
   FileOnnet: = 'URL MY';
    LocalFileName: = 'My.my';
    If GetinetFile (Fileonnet, LocalFileName) = True
     ShowMessage ('Download Successful')
    ELSE.
     ShowMessage ('Error in File Download');
  end;

Here, and the compiler problem is:

[Error] Unit1.pas (32): undeclared identifier: ‘getinetfile’

What is the problem? In UseS module connected.

Answer 1, Authority 100%

The essence of the error you seem to understand. Make sure the exactly the desired module is connected to the Uses section.
Make sure the feature name you wrote in the desired register.
Ensure that the feature takes such parameters.
Try clamping Ctrl and click on the mouse by name.

Answer 2

You call the getinetfile function, and it is not described anywhere. Here are 2 options: or write the function itself, or copy from there, where you have screamed the rest of the code. And uses here.