page location of itunes to download

Are you, by any chance, referring to the figure in step 3 of the 'Sync or remove content using iTunes' section in:

Use iTunes to sync your iPhone, iPad, or iPod with your computer - Apple Support

The only other page that I know of for the Mac is:

How to back up your iPhone, iPad, and iPod touch with your Mac - Apple Support

Exactly what are you trying to backup? See the 'Backups from your computer' section in:

Backup methods for iPhone, iPad, and iPod touch - Apple Support

Content from the iTunes and App Stores, or PDFs downloaded directly to Apple Books and Content synced from Finder or iTunes, like imported MP3s or CDs, videos, books, and photos are not included in the backup since they are already on your computer within iTunes.