Training institute seeks coaching software (collaboration)

My Swiss company offers coaching, seminars, courses, and continuing education. I am looking for coaching software because my business model has changed in that I am now coaching more and more entrepreneurs on an individual basis. I meet with them in person or online. The problem is that the client communicates via phone, WhatsApp, email, etc. Then individual or small group sessions are held online, and there is a data storage facility for the client where shared documents can be stored. I am currently trying to handle this using specific conference and communication software. It would be ideal if the client had central access. Perhaps this is also possible with a mobile app. The seminar management software we use still meets our requirements. Both business and private customers are served.

The following functions and requirements are what I have in mind:

• Appointment management - invitation - reminder to customer
• Secure audio and video sessions (encrypted)
• 1:1 coaching
• Groups - active involvement of participants, not just one-way communication
• Chat function
• Working on things together (whiteboard, documents)
• File storage with permissions (customer, group)
• Tasks, assignments, emails to customers between appointments
• Web-based
• Optional time tracking for billing per customer

There may also be a clever solution in MS Office 365.

One software workstation is planned. We work with MS Windows and Android systems.