The story
Originally a call for streamers on the online platform Twitch to type “F” in chat windows as a way to express sympathy when an unfortunate event occurs. This refers to the prompt “Press F to Pay Respects” in the PC version of the video game Call of Duty: Advanced Warfare (2014) which directs the player during a funeral cut scene to press the F key to touch the coffin of a soldier who was killed in battle saving the player’s life. The prompt became a meme, where people would be asked to “press F to pay respects” in non-gaming contexts to suggest that credit, recognition, or sympathy should be given.
Etymology from Wiktionary, CC BY-SA 4.0.