Affidavit of Name Change. If you go by a name different than your birth name but have not gotten around to officially changing it through the court, use an affidavit of name change. Typically, another person (most often your spouse or a blood relative) will sign this and swear that you use a name different from your what is on your birth certificate.
An affidavit is a statement made under oath that some fact, or set of facts, is true to the best of knowledge of the affiant. Affidavits are usually used to provide sworn statement of facts to the Courts or any other government agencies. Affidavits are usually sworn to before a Notary Public or before any other officer that has authority to administer oath. If false testimony was given in an affidavit form, the affiant or the person who executed said affidavit, exposes himself against prosecution for the crime of perjury or giving false statement under oath.
Affidavit of Small Estate. Small estates generally have an easier path through the probate process. You can use this affidavit to inform the court that the estate in question actually qualifies as a "small estate", which is usually capped around $150,000. Note that residents of New Hampshire, Kentucky, and Georgia should not use this document.
Affidavits can be used for many different reasons, but they all share a common trait: the person singing is making a declaration, under oath, that what is in the affidavit is true.