Free Will and Narritive Necessity

In any TTRPG, you play your character, and it is your character. The player calls the shots. The DM doesn't get to say "Ambur decides to go to the pub". That's the player's call! The obvious exception is that the player can't decide to do anything 'impossible' or rule breaking without the DM's approval. They also can't Meta-Game (See Mystery and Meta-gaming.)
The flip side of this is called Narrative Necessity. The player can make any choice they think is right, but they need to keep in mind the needs of the story: the Narrative Necessity. For example, when the mysterious stranger asks the party for help saving his daughter from bandits the player can say "my character isn't interested in rescuing maidens". But if they keep playing like that, there is no story. The stranger is an obvious plot hook (perhaps too obvious. A good DM would make it a little more interesting). The player needs to take the next step, which is "and therefore".
To continue, the player might say "my character isn't interesting in rescuing maidens; and therefore, she asks 'what's in it for me?'." This allows the player to control their character while continuing the plot. All while maybe negotiating more loot.
Another part of Narrative Necessity is sometimes called "Game Master's Fiat". This is when things happen simply because and there's no getting out of it. It's needed to advance the story. Everyone knows that the original Star Wars ("Episode IV: A New Hope") would have been a lot shorter if some cheapskate on the Devastator had just blown the escape pod out of the sky over Tatooine. Scratch two droids and one set of plans. Story over.
But Narrative Necessity demanded that the plans make it to Obi Wan, and so the Empire saved a few credits on ammo and sacrificed a base too small to be a moon, but too large to be a space station.
In the game, this will happen. There will be times when NPCs die, items are stolen, bridges collapse, and other calamities. All without any rolls, or any way for the party to prevent it. No wards, bodyguards, or precautions will help. Normally these will not affect the PCs; that would be cheating. But when Johnny leaves a note for your character to meet him in the back of the Mended Drum so he can give you all the information you need to defeat the BBEG in one fell swoop, you better believe that poor Johnny will be found dead in the back alley with his jaw and skull shattered. No speak with dead for you. This isn't cheating, it just the story.
Footnote: In some cases where the PCs have gone to extraordinary lengths within the story and the nature of their characters, Narritive Neccessity has been foiled. But only very rarely.