Web to Cross-Platform Mobile App

I'm in need of a skilled developer to create a cross-platform mobile app (iOS and Android) from an existing website. The main goal is to enhance accessibility of the website by transforming it into an app, while maintaining the registration and login system functionality.

Key Requirements:
- Convert the website to a mobile app
- Ensure compatibility with both iOS and Android platforms
- Prioritize incorporation of 'User Registrations/Login Systems'

Ideal Skills:
- Proficient in iOS and Android development
- Familiarity with web source code
- Experience in creating cross-platform mobile applications
- Strong understanding of authentication systems
preferred language kotlin others java