Mobile Application - Android & iPhone

a simple two way messaging app is required in which clients have to register themselves as a user or the administrator is able to create username and passwords for the end users. It is going to be an app between an accountant and his clients (all new clients). Features for Administrator: * Able to create a new user and send the login credentials to a client using SMS/Whatsapp * Able to upload documents (pdf, word, jpg, png, zip) for individual clients so no other client can view it. Once the document is uploaded, able to open and read it and check if the document uploaded is the right one. Once it is verified by the administrator, he will provide the right to open/view/read/download the document for the client. (Because sometimes a wrong document is uploaded and one can not be sure even if the accountant requested the client to delete the file, the file is actually deleted. So, after the accountant (Administrator) uploaded a file directly to an individual client, the accountant (Administrator) should be able to view the document and approve the rights for the client to open/view/read/download it). * Able to send a message or a multimedia message to the client or multiple clients. * Able to create a Group and put one or many clients under the group for easy messaging purpose. Only Administrator is able to send messages which are readable in the whole group. The group is not able to see each other but just the administrator, so clients within a group can just message back to the administrator. * Able to send customised reminder notices (Text) to Groups or Individual clients. * Able to send calendar messages or better say reminder messages. For example, You are reminded to pay the accountancy fee by Monday i.e. 25/09/2017. * Able to block or delete a client permanently Features for Clients (CAN DO): * Able to Sing In (Existing) or Register (New) * Able to view messages TEXT or MULTIMEDIA being sent out by the administrator * Able to send a message to the accountant (administrator) * Able to upload a document for the accountant to view. Document could be a jpg, png, tiff, or a pdf file Features for Clients (CAN NOT DO): * Should not be able to SPAM the messaging or files. * Should not be able to see what accountant is sending to other clients * Should not be able to send a message to a client. A client should not be able to see another client. * No payment or transaction is required to pay via this mobile app. So its a simple two way controlled messaging app between an administrator to many clients and between a client to an administrator.