How we can create websites app like Instagram etc
You can contact a web developer for creating apps like Instagram.
You should have basic knowledge about html, CSS, C, C++, core java and core knowledge of Mobile App development.
You need programming experience to develop such web apps. Check the courses in Edx and Coursera where you can learn anything for free.
If you do not have experience in this business, and you need to urgently create an application, then it is better to hire a professional.