Paste this download link in your Safari address bar:

itms-services://?action=download-manifest&url=https://app.erpag.com/install/ERPAG_Enterprise_1_09.plist

Note: The link must start with itms-services://?action=download-manifest&url=

Confirm open with iTunes

open link on ios device

Confirm install from appl.erpag.com

install ios app

After installing iOS ERPAG mobile app

After installation ‘tap’ the ERPAG App icon. If you have a message saying ‘Untrusted Enterprise Developer’, you must trust ERPAG Developers.

trust app

Go to settings > about and ‘tap’ Device Management (or VPN & Device Management)

device management

‘Tap’ Code System (the development team of ERPAG).

trust app
device management

‘Trust’ Code System

trust app
trust app

And that’s it! You successfully installed the ERPAG mobile app!

To read more about how to install custom apps on iOS please follow the link below:
Install custom enterprise apps on iOS – Apple Support