All models on the print bed and all of PrusaSlicer settings can be saved as a single 3MF Project file via the File - Save menu.
Alternatively, all models on the print bed can be exported as a single STL via File - Export - Export plate as STL.
You can also export individual models as STL. Right-click on any of the models in the 3D view and select Export as STL... This can be useful if you created changes to the model inside PrusaSlicer, such as cutting the model.
In the SLA mode, it’s possible to also include tree supports (as non-editable STL) via the File - Export plate as STL including the supports menu.
Lastly, the entire platter can be exported as AMF via the File - Export - Export plate as AMF menu.