Is it necessary to create Terms and Conditions in an application developed with firebase (Auth, real database and storage)?
I get Mac and email always. If the user want NickName, Social Networks Accounts, age, sex, and interests.
If its necessary, some example?
If you are developing a product that uses Firebase you should be doing a careful read of the Firebase Terms of Service yourself, or seek legal advice on the matter. StackOverflow probably isn't going to be a good place to get advice of this nature.
It is clear from the Firebase documentation that different Firebase products carry their own policies that you should adhere to. You'll need to review the policies of each product. Firebase Analytics, for example, indicates notifications that must be provided to users in the Google Analytics for Firebase Use Policy.
Your users deserve to know how their data is being handled, stored, used, etc. Let them know!