As an independent author, you are a small business. You are responsible for every aspect of your business. Everything from editing the content of a book to the cover is needed. That means you will need outside assistance. When you work with others you need an agreement between yourself and that party. The agreement is there to list expectations in addition to protecting you and them. This is where contracts are needed.
A contract is a legally binding agreement between two parties that include an offer, acceptance, considerations, competency, and of course legal intent. There are different tasks you will need to reach out to others to handle. A few are listed here and the type of agreement you should require.
Attorney (Standard & Entertainment)
Book Cover Designers
When dealing with contracts, always…always turn to legal authority.