Where is the iPhone backup file located on my Windows computer? I created the backup with iTunes for Windows.

If you used iTunes for Windows to create a backup of your iPhone, the backup file will be located in the "C:\Users\{userid}\AppData\Roaming\Apple Computer\MobileSync\Backup" folder.

A sub-folder will be created for each backup. For example, here is an iPhone backup sub-folder:

 Directory of C:\users\fyicenter\appdata\Roaming\Apple Computer\MobileSync
    \Backup\45219035443f09dccbcc469473f487ca5aee9f5a

03/23/2019  09:51 PM    <DIR>          00
03/23/2019  09:51 PM    <DIR>          01
03/23/2019  09:51 PM    <DIR>          02
03/23/2019  09:51 PM    <DIR>          03
...
03/23/2019  09:51 PM    <DIR>          fd
03/23/2019  09:51 PM    <DIR>          fe
03/23/2019  09:51 PM    <DIR>          ff
03/23/2019  09:51 PM           547,804 Info.plist
03/23/2019  09:50 PM        16,957,440 Manifest.db
03/23/2019  09:50 PM            31,623 Manifest.plist
03/23/2019  09:51 PM               189 Status.plist
               4 File(s)     17,537,056 bytes

⇒ Restore iPhone Backups from iTunes on Windows

⇐ Back Up iPhone with iTunes on Windows

⇑ Manage iPhone from iTunes on Windows

⇑⇑ Apple Music and iTunes Frequently Asked Questions