When you do normal writing, it's in the form of a sentence, with a period used to end the sentence. When you write a line of code, it's called a statement, with a semicolon used to end the statement. This is necessary because the console reads the code one line at a time and it's necessary to use a semicolon to tell the console that the line of code is over and that the console can jump to the next line. (This is happening so fast that it looks like the computer is reading all of them at the same time, but it isn't.) When we start learning how to code, forgetting about this detail is very common, so don't forget to check for this error if the code isn't working:
The reason a statement ends with a semicolon is so that Unity knows when the statement ends. A period can't be used because it is used in the dot syntax...