What is the process for members of Congress and other elected officials to access classified information?

Mildly curious since I saw the news today about House Republicans going into a SCIF with some PEDs and in a couple cases even tweeting while inside. I know if I did that I’d be really deep ■■■■, but I also know not to do that because I’ve signed multiple pieces of paper about how to conduct myself in classified areas and in regards to PEDs. I know that as elected officials, members of Congress and the President are entitled to access classified information without going through the entire process the rest of us do, but are they still subject to signing non-disclosures, briefings, indoctrination, and so on before they get access and get read off when they leave office?