[Home](./index.md) > [@firebase/auth](./auth.md) > [linkWithPhoneNumber](./auth.linkwithphonenumber.md) ## linkWithPhoneNumber() function Links the user account with the given phone number. Signature: ```typescript export declare function linkWithPhoneNumber(user: User, phoneNumber: string, appVerifier: ApplicationVerifier): Promise; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | user | [User](./auth.user.md) | The user. | | phoneNumber | string | The user's phone number in E.164 format (e.g. +16505550101). | | appVerifier | [ApplicationVerifier](./auth.applicationverifier.md) | The [ApplicationVerifier](./auth.applicationverifier.md). | Returns: Promise<[ConfirmationResult](./auth.confirmationresult.md)>