As this type of work is completely based on modern technology, a client would always like to hire someone who has a thorough knowledge of modern mobile devices and their operating systems. The same mobile app can operate differently on different operating systems that are why your client expects you to know the difference between android apps and iOS apps.
A little mistake or wrong command on a code can change the whole purpose of a mobile app that is why transparency and accuracy is a must if you want to impress your client. Punctuality is also required here as this particular job sector is ever changing and one delayed action can cost your client thousands of dollars. Surely don’t want to do that, do we?