Have look in Resource/Reference at the top of the page (or just about every IDE example or program on these forums) for the correct format of an if statement. HINT it needs the () brackets.
Computers can't "understand" language like people can (usually). They only follow a strict set of rules to know what to do. That is why you have to learn and follow the rules exactly.
Look at this. And remember when your compiler throws an error look at ALL the errors it throws not just one. Also the “=“ is for assignment only, “==“ tests the condition.
int CrashSwitch = digitalRead(2);
if (CrashSwitch == HIGH) {
digitalWrite(Buzzer, HIGH);
}