The Axsy Public Sector Mobile App supports Salesforce's Page Layout customisation. This means that it is possible to add and remove Fields and Related Lists that are made available on Salesforce in the Axsy app. 

You can add the Notes & Attachments Related List to the Related List section of a Visit, so that it will display in the Related tab of the Axsy app. 

Please see this Salesforce Page for more information on how to configure Salesforce's Page Layouts: Page Layouts