Copy. You'll need to remove the tracks from the original location yourself; after confirming that they're working correctly from the new location, of course. Make sure you use the correct procedure for moving; if you do it wrong, you'll break iTunes' links to the tracks.
Copy. You'll need to remove the tracks from the original location yourself; after confirming that they're working correctly from the new location, of course. Make sure you use the correct procedure for moving; if you do it wrong, you'll break iTunes' links to the tracks.
remove the contents from iTunes and then copy to external drive and then change the location in iTunes
That procedure won't work at all. You'll break all iTunes' links, and while you could use the Add To Library command to get all the tracks back in, all your playlists will be broken and you'll lose all the ratings, etc.
just change the location and let iTunes copy the files
That'll work if you change the location in the iTunes Advanced preferences and then use the Consolidate command.
The easiest way, though is to just drag the entire iTunes folder (the entire folder, not just the iTunes Music folder) to your desired location. Then hold down the Option key while launching iTunes. You'll be given a dialog box where you can select the iTunes library you want to use. Navigate to and select the iTunes folder in it's new location. Everything - playlists, ratings, etc. - should remain intact and all future purchases and imports should go to the new location on the external drive. Plus you can use that same iTunes library, with all of it's playlists, etc., on any computer you wish by similarly launching iTunes and holding down the Option key (Shift on a Windows system). Just a heads-up: if you launch iTunes without the external drive being mounted, iTunes will default back to using the internal drive. If that occurs, just quit iTunes, connect the external drive, and launch iTunes with the Option key.
Make sure you're holding down the Option key before you click to launch iTunes, and keep holding down the key until you get the dialog box with the options to select a library or create a new one.
If you're certain that everything has been copied correctly to the external and is working properly in iTunes, then yes, you can if you wish delete the original folder, or the iTunes Music folder within it, from the internal hard drive.