public void Sign(
    Stream inputStream,
    Stream outputStream,
    SignatureOptions options,
    SignatureInfo signatureInfo
)

Public Sub Sign(
    inputStream As Stream,
    outputStream As Stream,
    options As SignatureOptions,
    signatureInfo As SignatureInfo
)

using DevExpress.Office.DigitalSignatures;
using System;
using System.Diagnostics;
using System.Security.Cryptography.X509Certificates;

static void Main(string[] args)
{
    //Sign a workbook:
    using (Stream stream = new FileStream("Template.xlsx", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        using (Stream outputStream = new FileStream("Workbook_signed.xlsx", FileMode.Create, FileAccess.Write, FileShare.Read))
        {
            SignDocument(stream, outputStream);
        }
    }

    //Sign a document:
    using (Stream stream = new FileStream("Template.docx", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
    {
        using (Stream outputStream = new FileStream("Template_signed.docx", FileMode.Create, FileAccess.Write, FileShare.Read))
        {
            SignDocument(stream, outputStream);
        }
    }
}
static void SignDocument(Stream path, Stream output)
{
    DocumentSigner documentSigner = new DocumentSigner();
    documentSigner.Sign(path, output,
     CreateSignatureOptions(), CreateSignatureInfo());
}

//Specify a signature certificate and digest method:
static SignatureOptions CreateSignatureOptions()
{
    X509Certificate2 certificate = new X509Certificate2("Certificate/SignDemo.pfx", "dxdemo");
    Uri tsaServer = new Uri("https://freetsa.org/tsr");
    SignatureOptions options = new SignatureOptions();
    options.Certificate = certificate;
    if (tsaServer != null)
        options.TsaClient = new TsaClient(tsaServer, HashAlgorithmType.SHA256);

    //In this example, certificate validation is skipped
    options.SignatureFlags &= ~SignatureFlags.ValidateCertificate;
    options.CertificateKeyUsageFlags = X509KeyUsageFlags.None;
    options.DigestMethod = HashAlgorithmType.SHA256;

    X509ChainPolicy policy = new X509ChainPolicy();
    policy.RevocationMode = X509RevocationMode.NoCheck;
    policy.RevocationFlag = X509RevocationFlag.ExcludeRoot;
    policy.VerificationFlags |= X509VerificationFlags.AllowUnknownCertificateAuthority |
        X509VerificationFlags.IgnoreCertificateAuthorityRevocationUnknown;
    options.CertificatePolicy = policy;
    options.TimestampCertificatePolicy = policy;
    return options;
}

//Specify signer information:
static SignatureInfo CreateSignatureInfo()
{
    SignatureInfo signatureInfo = new SignatureInfo();
    signatureInfo.CommitmentType = CommitmentType.ProofOfApproval;
    signatureInfo.Time = DateTime.UtcNow;
    signatureInfo.ClaimedRoles.Clear();
    signatureInfo.ClaimedRoles.Add("Sales Representative");
    signatureInfo.Comments = "Demo Digital Signature";

    return signatureInfo;
}

Imports DevExpress.Office.DigitalSignatures
Imports System
Imports System.Diagnostics
Imports System.Security.Cryptography.X509Certificates

Shared Sub Main(ByVal args() As String)
    'Sign a workbook:
    Dim workbookOutput As String = "Workbook_signed.xlsx"
    SignDocument("Template.xlsx", workbookOutput)

    'Sign a document:
    Dim documentOutput As String = "Document_signed.docx"
    SignDocument("Template.docx", documentOutput)
End Sub

Shared Sub SignDocument(ByVal path As String, ByVal output As String)
    Dim documentSigner As New DocumentSigner()
    documentSigner.Sign(path, output,
     CreateSignatureOptions(), CreateSignatureInfo())
    Process.Start(output)
End Sub

' Specify a signature certificate and digest method:
Private Shared Function CreateSignatureOptions() As SignatureOptions
    Dim certificate As New X509Certificate2("Certificate/SignDemo.pfx", "dxdemo")
    Dim tsaServer As New Uri("https://freetsa.org/tsr")
    Dim options As New SignatureOptions()
    options.Certificate = certificate
    If tsaServer IsNot Nothing Then
        options.TsaClient = New TsaClient(tsaServer, HashAlgorithmType.SHA256)
    End If

    'In this example, certificate validation is skipped
    options.SignatureFlags = options.SignatureFlags And Not SignatureFlags.ValidateCertificate
    options.CertificateKeyUsageFlags = X509KeyUsageFlags.None
    options.DigestMethod = HashAlgorithmType.SHA256

    Dim policy As New X509ChainPolicy()
    policy.RevocationMode = X509RevocationMode.NoCheck
    policy.RevocationFlag = X509RevocationFlag.ExcludeRoot
    policy.VerificationFlags = policy.VerificationFlags Or X509VerificationFlags.AllowUnknownCertificateAuthority Or X509VerificationFlags.IgnoreCertificateAuthorityRevocationUnknown
    options.CertificatePolicy = policy
    options.TimestampCertificatePolicy = policy
    Return options
End Function

' Specify signer information:
Shared Function CreateSignatureInfo() As SignatureInfo
    Dim signatureInfo As New SignatureInfo()
    signatureInfo.CommitmentType = CommitmentType.ProofOfApproval
    signatureInfo.Time = Date.UtcNow
    signatureInfo.ClaimedRoles.Clear()
    signatureInfo.ClaimedRoles.Add("Sales Representative")
    signatureInfo.Comments = "Demo Digital Signature"

    Return signatureInfo
End Function