I need help for my final year project
There isn't an obvious api with QGIS . I expect the simple answer is you cannot transfer data from QGIS to App Inventor unless QGIS produces downloadable files that can be read by App Inventor.
It might be possible to use some of the data QGIS can export,' I think you may be able to work with the highlighted entries shown here:
"You can create, edit, manage and export vector and raster layers in several formats. QGIS offers the following:
Vector digitizing tools
Ability to create and edit multiple file formats and GRASS vector layers
Georeferencer tool to geocode vectors and images
GPS tools to import and export GPX format, and convert other GPS formats to GPX or down/upload directly to a GPS unit (on Linux, usb: has been added to list of GPS devices)
Support for visualizing and editing OpenStreetMap data
Ability to create spatial database tables from files with the DB Manager plugin
Improved handling of spatial database tables
Tools for managing vector attribute tables
Option to save screenshots as georeferenced images
DXF-Export tool with enhanced capabilities to export styles and plugins to perform CAD-like functions
QGCIS says it can export gpx files, App Inventor may be able to handle some the QGCIS programs creates:
🛤️ How to import, create and use gpx and kml track files to App Inventor Map
Good luck. Let us know what works (if anything 
)