To show possession for a singular noun, place an apostrophe followed by the letter "s" after the noun (e.g., "The cat's tail"). For plural nouns that already end in "s," just add an apostrophe after the "s" (e.g., "The dogs' toys"). Contractions are formed by placing an apostrophe in place of omitted letters (e.g., "can't" for "cannot" or "he's" for "he is").
