# Extend your integration

Extend your Tap to Pay on iPhone integration with refunds, transaction reporting, tips, taxes, line items, and surcharges.

**Prerequisites:** [Authentication](/api/authentication) · [Run a sale](/guides/payments/tap-to-pay-on-iphone/run-a-sale)

After you set up your app to run a sale, you can extend your integration to include the following:

- [**Run a refund**](/guides/payments/tap-to-pay-on-iphone/run-a-refund) - Return funds to the same card that the customer used for the original sale.
- [**Retrieve transactions**](/guides/payments/tap-to-pay-on-iphone/retrieve-transactions) - Retrieve a single transaction or list multiple transactions.
- [**Add a tip to a sale**](/guides/payments/tap-to-pay-on-iphone/add-a-tip) - Add a predefined tip or a custom tip to a sale.
- [**Add a tax to a sale**](/guides/payments/tap-to-pay-on-iphone/add-a-tax) - Add a predefined tax or a custom tax to a sale.
- [**Add a line item to a sale**](/guides/payments/tap-to-pay-on-iphone/add-a-line-item) - Add itemized product details to a sale.
- [**Handle surcharges**](/guides/payments/tap-to-pay-on-iphone/handle-surcharges) - Present a surcharge fee to the customer for confirmation.
- [**Cancel a sale**](/guides/payments/tap-to-pay-on-iphone/cancel-a-sale) - Cancel an in-progress sale, and handle the cancellation status that the SDK returns.
- [**Run the sample apps**](/guides/payments/tap-to-pay-on-iphone/run-the-sample-apps) - Run the Swift or Objective-C sample app from the SDK package.

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## Guides

To extend your Tap to Pay on iPhone integration, follow our guides:

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#### [Run a refund](/guides/payments/tap-to-pay-on-iphone/run-a-refund)

Refund a sale to the same card.

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#### [Retrieve transactions](/guides/payments/tap-to-pay-on-iphone/retrieve-transactions)

View your sales and refunds.

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#### [Add a tip to a sale](/guides/payments/tap-to-pay-on-iphone/add-a-tip)

Add a predefined or custom tip.

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#### [Add a tax to a sale](/guides/payments/tap-to-pay-on-iphone/add-a-tax)

Add a predefined or custom tax.

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#### [Add a line item to a sale](/guides/payments/tap-to-pay-on-iphone/add-a-line-item)

Add itemized product details.

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#### [Handle surcharges](/guides/payments/tap-to-pay-on-iphone/handle-surcharges)

Present a surcharge for confirmation.

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#### [Cancel a sale](/guides/payments/tap-to-pay-on-iphone/cancel-a-sale)

Cancel an in-progress sale.

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#### [Run the sample apps](/guides/payments/tap-to-pay-on-iphone/run-the-sample-apps)

Run our Swift or Objective-C sample app.