> For the complete documentation index, see [llms.txt](https://docs.sign.enadocapp.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sign.enadocapp.com/how-to-send-signature-request/how-do-you-add-authentication-to-your-request.md).
# How do you add authentication to your request?
The authentication feature has two options:
1. Email OTP (One Time Password)
2. Access code
Check out how each authentication type works:
OTP (EMAIL/SMS)
*A six-digit verification code auto-generated by the Evia Sign.* You have the option of sending this OTP to the signatory's phone number, the email address, or both.
Access code
The signature requester *can specify a verification code of their choice. In this case, the verification code will be directly communicated to the signatory(s).*
Follow the detailed steps below to set up authentication:
* Select the signatory to whom you want to set up the authentication option and enable authentication by clicking the toggle switch to activate the feature.
* Select one of the authentication options.
* This action will assure that an email OTP or an access code is always requested from the signatory when proceeding to open and sign the document.
{% hint style="info" %}
In the case of multiple signatories, follow the same procedure.
{% endhint %}