A master service agreement (MSA) is a legal contract that establishes fundamental agreements between two parties. MSAs allow vendors and clients to agree on basic terms at the outset of a business relationship before any business commences.

A purchase agreement is a contract generally used in transactions where the buyer is purchasing goods instead of services. This type of contract is most common in complex and expensive transactions, such as purchasing real estate or large, specialized equipment.

A quote is an itemized accounting of products or services to be rendered in a business transaction. Quotes differ from invoices in that invoices in that they are typically provided to the customer before work begins and/or products are officially purchased.

A statement of work (SOW) is a document that describes in detail how a project will be executed. The purpose of an SOW is to ensure all parties are aligned on scope, deliverables, execution, and payment before signing an agreement.

An invoice is a written document that lists and itemizes goods and services provided to the recipient. It briefly describes the transactions completed, the associated cost of each of these transactions, and the terms of payment requested by the party who completed them.

A lease addendum is a document that is added to an existing lease agreement to introduce additional terms, conditions, or provisions without altering the original lease terms.