According to IFRS 15, an entity can identify a performance obligation in a contract by considering the following steps:

1. Identify the Promised Goods or Services: In the contract, identify all the promised goods or services. This could include goods, services, rights to goods or services, or other performance obligations.
2. Determine if Goods or Services are Distinct: A good or service is distinct if the customer can benefit from the good or service on its own or together with other resources readily available to the customer, and the promise to transfer the good or service to the customer is separately identifiable from other promises in the contract.
3. Consider Bundles of Goods or Services: If a series of goods or services are substantially the same and have the same pattern of transfer, they can be considered as a single performance obligation.
4. Evaluate if Performance Obligations are Satisfied over Time or at a Point in Time: Consider whether the customer receives and consumes the benefits as the entity performs, whether the customer controls the asset as it is created or enhanced, or whether the entity's performance does not create an asset with an alternative use and the entity has the right to payment for performance to date.
5. Apply Professional Judgement: Sometimes, identifying performance obligations might require significant judgement. In these cases, the entity should apply judgement, taking into account all relevant facts and circumstances.

Identifying performance obligations is crucial in a contract because it determines how and when an entity will recognize revenue from a contract with a customer. The transaction price in the contract is allocated to each performance obligation based on their relative standalone selling prices, and revenue is recognized when (or as) each performance obligation is satisfied.