> For the complete documentation index, see [llms.txt](https://docs.vida.id/identity-stack/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.vida.id/identity-stack/sign/digital-signature/directsign-api/api-reference/choose-signer.md).

# Choose Signer

As a licensed **PSrE**, VIDA issues and leverages **Komdigi-rooted certificates** to sign documents through the **DirectSign API**. To ensure the correct user certificate is applied, the client must specify which signer will sign the document.

VIDA provides two methods for signer identification:

1.  Signer Verified by VIDA
   1. For clients who use VIDA’s verification suite to verify a user and issue a digital certificate:
   2. Use the **`kyc_event_id`** to sign documents.
2. Signer Not Verified by VIDA
   1. For clients who already have their own authoritative source to verify signers:
   2. Use the **Registration API** to submit pre-verified user data for certificate issuance
   3. Use the **`registrationId`** to sign documents.