# Introduction

With this API you are able to authorize users and sign hashes of documents.

To sign document you need to follow this steps:

1. Login user
2. Verify user session
3. Get user certificate
4. Initialize user authorization
5. Authorize user using the SMS code (OTP token)
6. Sign the document

To use this API, you need to import the .p12 certificate, which was provided by our team, or the certificate generated by you, which we imported into our truststore.

<figure><img src="/files/xt33woXYkKB7PA8Ick0N" alt=""><figcaption></figcaption></figure>


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.signius.eu/api/harmony-api-1/introduction.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.