--- title: "Upload mobile phone number" method: PUT path: "/v1/onboarding/signatures/{workflowId}/data" tags: ["Qualified Electronic Signature"] --- # Upload mobile phone number `PUT /v1/onboarding/signatures/{workflowId}/data` Use this endpoint for Qualified Electronic Signature workflows to upload the client’s mobile phone number.

Important **Important:**
• Before using this endpoint, see the integration guide.
• signatureId and workflowId are string identifiers that can be used interchangeably. ## Path parameters - `workflowId` string, required ## Headers - `Authorization` string, required — The `access_token` returned in your most recent [Create access token](https://docs.fourthline.com/reference/create-access-token) response. ## Request body - object - `mobilePhoneNumber` string, required — The client’s mobile phone number, which you have ensured is valid.

Format: +prefixNumber phoneNumber

Example: `+31 612345678`
**Notes**:
• Always include a **space** between the prefix and phone number.
• The prefix can contain a maximum of **4** digits.
• If creating a test signature that you will confirm with a [test passcode](https://docs.fourthline.com/reference/get-test-passcode), you must provide a dummy mobile phone number in the following format: `+39 111111234567`. You can change digits `234567` as required ## Response `202` Mobile phone number upload accepted - object — The request was accepted. The response body is empty. ## Other responses - `400` — Invalid request parameters - `404` — Signature not found --- [API](https://skmtc.net/fourthline/apis/fourthline-apis.md) · [All operations](https://skmtc.net/fourthline/apis/fourthline-apis/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/fourthline/fourthline-apis/revisions/7991ae7c8383/schema)