Attendance Tracking App Development

I need an application to track the attendance of all trainers and sessions done/not done by clients, complete with a proof system. This will be used by our head coach to manage trainer performance and client engagement.

Key Features:
- Attendance tracking via:
- Manual check-in
- QR code scanning
- Photo upload

- User Roles:
- Trainers and coaches
- Clients
- Sales staff and callers

- Automated WhatsApp messaging system for client engagement, referrals, and renewals.

Requirements:
- The system must be user-friendly, even for individuals with limited tech experience.
- Must work on both iOS and Android platforms.

Ideal Skills & Experience:
- Mobile app development (iOS & Android)
- User-friendly interface design
- Experience with attendance tracking systems
- Familiarity with WhatsApp API for automation
- Background in managing applications for multiple user roles