Dear Sir,
I'm writing to express my interest in executing your project, I'm skilled in iOS and Web (front-end, backend) Development.
I'm teamed up with my brother who is skilled Android developer. Together we have advanced proficiency in Swift, Obj-C, Kotlin, PHP, Javascript, jQuery, HTML5/CSS3, and excellent familiarity with Android SDK.
I can also provide code samples of my previous work, or if you have any test task in mind, I'm also available to go through so I can prove my skills.
I thank you for your time to read my proposal. I look forward to hearing from you soon.
Aamir