Control: How To Get Clearance Level 1
Control seamlessly blends supernatural and mundane elements, with much of its mechanics and worldbuilding tied to reports, items, and procedures that would fit right in at a real government agency. Drawing on this inspiration, Remedy has scattered several locked doors throughout the Oldest House. These doors require varying clearance levels to open, which you must collect to progress through the game and discover all it has to offer.
When Jesse arrives at the Federal Bureau of Control's secret headquarters, she does not have a clearance level. Remedy introduces the mechanic as part of "Unknown Caller," the game's second mission. To reach a certain Object of Power, you must gain access to the mail room through a locked security door which requires clearance level 1. In the area near the mail room door, you'll find the body of a dead guard slumped against a metal cabinet. Search the objects scattered in front of the corpse to obtain the clearance level 1 pass. With the pass, you can access the mail room and other doors of the same level, such as the one you encountered at the start of the game.
Note that you can check your clearance level under the Assets tab in the main menu. As you collect new passes, make sure you take the time to circle back through areas you've previously explored to unlock security doors once above your clearance level. Control boasts a large map that Remedy designed for a non-linear progression. To uncover all the collectibles and resources and complete the game's side quests, you must explore the various sectors and, in many cases, backtrack to areas you visited as part of the main narrative.