To obtain the artist ID follow the following steps:
1) Search any album of artist on iTunes
2) Click on artist's link
3) The ID appears after the letters "id" on the url (in the example the ID is 262836961)
3) The ID appears after the letters "id" on the url (in the example the ID is 262836961)
NOTE: Please, ensure that the URL is the artist page, not the album page. Format: https://itunes.apple.com/us/artist/[ ARTIST NAME ]/id[ ARTIST APPLE ID ]
Entering the Artist ID in the designated field ensures that each album, single, EP or ringtone is automatically assigned to the correct artist. This is especially important in those cases, in which the Artist or Band name already exists in the iTunes Store.