An agreement between two parties is a common occurrence in business transactions that involves a set of terms and conditions that both parties agree to abide by. Such an agreement creates an obligation to act for both parties, and it falls under the category of contract law.

The purpose of an agreement is to ensure that both parties receive a fair exchange of value for their actions. It is a legally binding document that outlines the terms and conditions of the transaction, which may include payment terms, delivery schedules, warranties and guarantees, and other obligations that both parties must fulfill.

Contract law is a fundamental aspect of business transactions, and it governs the legal relationships between parties. Generally speaking, a valid contract is one that involves a legally binding agreement between two or more parties, with the intention of creating a legal obligation to perform.

There are several elements that must be present for a contract to be legally valid, including offer and acceptance, mutual assent, consideration, and capacity. Offer and acceptance refers to the exchange of a promise to perform in exchange for something of value, while mutual assent refers to the parties` agreement to the terms and conditions of the contract.

Consideration refers to the payment, performance, or promise of payment or performance that each party will receive in exchange for fulfilling their obligations under the contract. Capacity refers to the legal ability of each party to enter into and fulfill the terms of the contract.

In conclusion, an agreement between two parties that creates an obligation to act falls under the category of contract law. A valid contract must fulfill several elements to be legally binding and enforceable. A well-crafted agreement, supported by an experienced legal advisor, can help ensure that both parties receive the benefits of their agreement, and avoid disputes and legal issues down the road.