Where to put the apostrophe in the word its?

The Word "its" does not require an apostrophe when indicating possession, as in "The dog chased its tail." However, "it's" with an apostrophe is a contraction for "it is" or "it has," as in "It's going to rain today." To determine whether to use the apostrophe, consider whether you mean possession (no apostrophe) or a contraction (with apostrophe).