The most common reasons for obtaining an appraisal are related to real estate and financial transactions. Some others could include:
The need for a loan
Lowering your taxes
Issues with property taxes
Estate settlement
For a lawsuit
An appraisal is looking at the financial value of the property, while a home inspector is looking at the structure, mechanical, electrical concerns regarding the property and does not determine value.
The estimated value
Why the appraisal was obtained
Who it is for
The type and definition of value being reported
Any easements, leases, special assessments, encumbrances, etc.
And more depending on the type of property.
Yes, you should have some documents ready for review, including, but not limited to: