How can I add a variable to console.log?

You can use another console method:

let name = prompt("what is your name?");
console.log(`story ${name} story`);

console.log takes multiple arguments, so just use:

console.log("story", name, "story");

If name is an object or an array then using multiple arguments is better than concatenation. If you concatenate an object or array into a string you simply log the type rather than the content of the variable.

But if name is just a primitive type then multiple arguments works the same as concatenation.

Then use + to combine strings:

console.log("story " + name + " story");