Where do periods go?

Periods can go a lot of places, but mainly at the end of a statement. Ex: I went to the mall to shop for new clothes. (This is called a declarative sentence)

Question marks go at the end of sentences as well. Ex: Where did that paper go? (This is called an interrogatory sentence)

Another common type of punctuation is the exclamation point or mark, which always appear at the end of a sentence. Ex: That ice cream was splendid! (This is known as an exclamatory sentence)

Hope this helped!