I need and Android application

General information for the app: Its basically going to be used by a small gorup of contractors linked to one admin
Kind of development: New app from scratch
Description of every page/module: 1- Users :
Host Admin , and contractor end user
Host Admin, will have a dashboard where admin can create quick descriptions of an jobs (inquiry , details of the jobs, location, and contact details of the requester) , and send them to specific contractor.
2- The contractor , Accepts or rejects the gig ,
2.1 if accepts its prompt to commit to a deadline date to contact the customer, which copies into its calendar and notifies the admin .
2.2 If not the admin receives a notification to send the gig to another contractor

3. Job Scenarios
3.1 On the spot, small jobs will be quoted and performed on the spot so the contractor will send the invoice request
3.2 the contractor meet the customer where he gather info for a proposal + materials
Here the contractor will itemize the proposal and communicate to the admin for them to create a proposal and send it to the customers.

4 Functions
the way to communicate is 3 option
a. 1 click voice recording in the app , where it click the voice recird funtion and when hit stop a message said are you done!! click OK and automatically send it to the admin, attached to the job where it comes from
2. With a template booklet for estimates he takes a 1 click picture in the app and replicates the voice message behavior
3. Pre created online form where the contractor can add lines per item and estimated price
Description of requirements/features: Critical
central communication to one admin user, the host admi will create the instances and the username for the end users (contractors) send the invite download the app with the credentials that he or she created for it .

Notification of progress and availability to create dead lines
Simple voice notes sending to admin dashboard (no need to be android host , can be a window or web receiver )
Simple pic Scan send feature,
Mobile form with the possibility to add items lines
force notifications from host to specific user and group notifications

Not critical , internal chat.
connection to calendar
Specific technologies required: only android for the contractor app
Extra notes: