If you are planning start iOS App development at your own or by hiring a team, you need following resources.
Mac machine
I suggest following computer configuration for smooth development:
Apple Mac Mini
Apple Mac Mini MGEN2HN/A – Intel Core i5, 8 GB, 1 Tb HDD 8 Mini PC
General Specifications:
Processor Type: Intel Core i5 or higher
Processor Speed: 3.1 GHz
RAM: 8 GB
Internal Storage Capacity: 1 Tb
Keyboard + Mouse: Any good brand like TVS or matching with display
Operating system: macOS
Display Unit:
Size: 22 inch or above
Screen Resolution: HD
Display Type: LED
Recommended Display:
HP 23.8 inch Full HD IPS Panel Monitor
Alternate (only if mobility is concern)
Apple MacBook Air Core i5 5th Gen – (8 GB/128 GB SSD/Mac OS Sierra) MQD32HN/A A1466 (13.3 inch, SIlver, 1.35 kg)
OR
Apple MacBook Air Core i5 5th Gen – (8 GB/256 GB SSD/Mac OS Sierra) MQD42HN/A (13.3 inch, SIlver, 1.35 kg)
Apple Developer Account
Xcode IDE
Register in iOS Developer Program (Optional)
Let me know if you need further assistance or any help.