On iPhone 16 Pro and iPhone 16 Pro Max with iOS 18.2 or later, you can create a layered recording by adding a vocal layer on top of an instrumental recording. (See separate the layers, each layer is in .m4a format and will appear on devices with iOS 18.1, iPadOS 18.1, macOS Sequoia 15.1, or earlier.
You can mix the two layers in a layered recording.
Go to the Voice Memos app edit them, and play them separately.
Note: The separated layers are in .m4a format and will appear on devices with iOS 18.1, iPadOS 18.1, macOS Sequoia 15.1, or earlier.