The Firemonkey Accessibility Pack for Delphi 10 Berlin is available from Embarcadero with support for JAWS on Windows and VoiceOver on Mac OSX. The Accessibility Pack docs show that the accessibility pack makes the MSAA and OSX Accessibility APIs available for you to access. You can implement the IFMXAccessibility interface in your own custom components to make available to the accessibility API. Additionally, it provides accessibility support for the following FMX components: TButton, TSpeedButton, TTracker, TEdit, TListBox, TComboBox, TComboEdit, TSpinBox, TLabel, TCheckBox, TRadioButton, TMainMenu, TMemo, TTreeView, and TCustomGrid. Adding accessibility to your existing projects is as simple as including the FMX.ScreenReader units at the top and changing your form class to TAccForm. You should be able to use the Accessibility Pack with C++Builder as well. There is no installer so simply uncompress the accessibility pack into your Embarcadero\Studio\18.0 directory with Administrator permissions. You can access the Delphi 10 Seattle Accessibility Pack here. If you need to impliment accessibility on your Android and IOS applications the documentation for the Android API is here and the docs for the IOS API are here.
FMXExpress.com has over 700 tips and tricks for building cross platform apps on Android, IOS, OSX, Windows, and Linux with a single codebase and single UI using the FireMonkey framework found in Delphi and C++Builder.
FMXExpress covers top cross platform secrets for FireMonkey in C++Builder and Delphi XE5, XE6, XE7, XE8, Seattle, Berlin, Tokyo, Rio, and Sydney.