1) In regards to editing the worldfile, here are a few tips to hopefully get it working (some are obvious but are pitfalls that might occur):
- Make sure that the 6 parameters are all specified correctly within the .tfw file
Overview of georeferencing—ArcGIS Pro | ArcGIS Desktop (scroll to the Transforming the Raster section)
- Make sure that the file name is correct (the .tfw file relies on the name to be exact)
- Make sure that your notepad saved out a .tfw file and not a .txt file for instance filename.tfw.txt is just a text file
- When using in ArcGIS Pro, make sure that your worldfile takes precedence over internal spatial references
- Click the Project tab
- Click Options > Raster and Imagery
- Expand the Raster Dataset tab
- Check the "Use worldfile to define the coordinates of the raster" check box
2) The Warp tool uses the concept of "from" and "to" ground control points, much like manual georeferencing would. It is in the form of a geoprocessing tool, where you must specify the all the point pairs. Unless you already have the coordinates of all the ground control points, this will not work for you.