I have programmed for 17 years and worked on large international projects using PHP. I've worked two years for International Software Technology developing a new e-learning platform in PHP/AngularJS. In another position I was working with a nation wide live web auction system in Norway. I have made an inventory system like this before. I can not reuse or resell the code but I have a strong understanding of what's needed.
I will build the application in two parts. The mobile app will be made cross platform so it will work for both Android and IOS. The other part will be the backend of the mobile app and the admin panel.
Mobile app:
User downloads inventory app
User scans his QR code to log in to your inventory system
User information is saved so user does not have to log in next time
User push scan button and scan a QR or UPC code
User can add/subtract to the amount, or set a new amount (easier if receiving box of 50 items)
Admin:
Secure user login
Can add/remove/disable users, QR codes are automatically generated
Can manage master inventory list
Master inventory list:
List all items (title, delivery time, restock amount, current stock)
Set restock amount
Shows warning if stock is less than restock amount
Click an item to go to a page with item details
Can add/remove/disable items, QR codes are automatically generated
Ability to select multiple items and print QR codes for them.
Single item:
Display optional item information
List of all transactions and who registed them