How to Programmatically Install an iOS App on USB-Connected iPhones from a macOS Application?

There's no way to do this without some kind of user opt-in.
I suggest using Apple Configurator for Mac, available for free from the App Store.

First, publish your app on the App Store as a free unlisted app, and publish it to the Enterprise App Store.
Then sign up for an Apple Business organization. You'll need this to obtain licenses for Configurator to distribute to devices (yes, even though it's free).
Run Configurator on the Mac, sign in to a user on the Apple Business account, and obtain licenses for your app. In Configurator's help there's an article "Assign apps to devices in Apple Configurator for Mac" that describes how to do this.
Then when it's time to install the app on a user's device, connect it to the Mac using a cable. The user will have to "trust" the computer by unlocking their device, tapping Trust, and entering their passcode.
After that, you can have Configurator automatically install the app on the phone.

Bob Whiteman - Device management engineer

Thank you for your detailed explanation. This approach sounds promising for our use case.

Our target customers are device refurbishment facilities and wholesalers processing large volumes of used iPhones, potentially 2,000 or more devices per shipment, with 30–50 devices connected to a Mac simultaneously.

We are comfortable requiring the operator to unlock the devices and approve the initial Trust This Computer prompt.

Before proceeding, could you please clarify two points?

1. After the operator trusts the Mac, can Apple Configurator install a free, unlisted App Store app onto these devices without supervising, erasing, or permanently enrolling them in MDM?

2. Can this licensed-app installation process be initiated programmatically through cfgutil or another supported interface, so it can be integrated into our own macOS application rather than requiring the operator to use the Apple Configurator interface separately?

We would also like to remove the diagnostic application after testing and move to the next batch of devices.

Thank you again for your guidance.

It is not necessary to supervise, erase, or enroll a device in MDM when using Configurator to install an app.

cfgutil has some capabilities, but it does not do what you need. However the full Configurator UI has a feature for this kind of workflow, where a technician is applying the same configuration changes to many devices. The technician selects the target devices and the blueprint to apply from a menu, and Configurator applies the changes. Blueprints cannot remove the app afterwards though. That would need to be done with a more manual operation in Configurator or on the device.

Thank you for your previous guidance regarding Apple Configurator, Blueprints, and installing applications without device supervision or MDM enrollment.

We have now confirmed the exact technical issue with our developer and would appreciate further clarification.

Current Implementation:

We have a macOS desktop application that installs an IPA onto iPhones connected via USB.

The IPA is currently signed using an Apple Development certificate and a development provisioning profile.

When our desktop application transfers and attempts to install the IPA, iOS displays the following error:

"Unable to Install — This app cannot be installed because its integrity could not be verified."

Our objective is to install the iOS application onto arbitrary customer-owned iPhones without registering device UDIDs or requiring Developer Mode.

We understand that development provisioning profiles are not suitable for this production use case.

Our Questions:

If we publish our iOS application as a free, unlisted App Store application, can we use that production distribution method to install it onto USB-connected iPhones without registering their UDIDs or enabling Developer Mode?

Can our existing macOS application programmatically initiate this installation, or must installation be performed separately through the Apple Configurator graphical interface?

Is there any Apple-supported API, framework, command-line tool, or distribution mechanism that allows third-party macOS applications to install App Store-distributed applications onto USB-connected, unsupervised iPhones?

If Apple Configurator is the only supported approach, can its Blueprint installation process be triggered programmatically from another macOS application?

Does installing an App Store-distributed app through Apple Configurator require any additional user interaction beyond trusting the computer and approving the installation where prompted?

Our Commercial Use Case:

Our customers are device refurbishment warehouses processing hundreds or thousands of used iPhones. They typically connect 30–50 iPhones simultaneously through USB hubs for hardware diagnostics, network checks, grading, and inventory processing.

We want to minimize manual installation steps while respecting Apple's security and authorization requirements.

We are not looking to bypass Apple's security protections. We want to replace our development-signed IPA installation approach with the correct Apple-supported production deployment method.

Could you please recommend the most appropriate technical implementation?

Thank you again for your assistance.