Current versions of iTunes don't run on Windows 7. Older versions are not going to be compatible with iOS 18. The older version might be potentially useful for adding music to an Apple Music library which could then sync to your device over the air.
- iTunes 12.10.11.2 for Windows (32-bit) - iTunesSetup.exe (2021-04-22) Last build to support Windows 7 & 8
- iTunes 12.10.11.2 for Windows (64-bit) - iTunes64Setup.exe (2021-04-22) Last build to support Windows 7 & 8
The iCloud for Windows is not used for device backups, iCloud backups are made over the air to Apple's servers.
Windows 7 is really rather old now and no longer getting security updates. You should really update to Windows 10 or 11.
tt2