Yes. This exectly.
Senator Casey and almost certainly Senator Fetterman will use a portal. The LOR (addressed to them individually, properly, and signed) needs to be sent to them according to the instructions they provide. It is possible that Sen. Fetterman will require as did his predecessor that the ENTIRE application (essay, transcript, all LORs, photo, etc) be sent in one single PDF document. Pay attention to the specific requirements.
I don’t know what district you’re in but it’s not uncommon for the U.S. Representative to come online or open up the application info much later than the senators, and run the due dates and interviews later as well.
These will not be due for a long time but may be due as early as Sept 1 so know that a portion if not all of this needs to be done by guidance and teachers over the summer.
Meet with each recommender before school ends. Have a clear description on paper for them on the requirements and due dates. Trust but verify that things get done and sent. They won’t be using their usual system (Naviance for most) and this may be something that requires extra steps etc than they’re used to. My son created a tracking system and followed up respectfully as needed but I recall it was ongoing throughout the summer because Senator Toomey had that early due date. Leadership and organization needed throughout this process that’s for sure!
Good luck and go PA!!