using System;
using System.Collections.Generic;
using System.IO;
using GroupDocs.Signature.Cloud.Sdk.Api;
using GroupDocs.Signature.Cloud.Sdk.Client;
using GroupDocs.Signature.Cloud.Sdk.Model;
using GroupDocs.Signature.Cloud.Sdk.Model.Requests;

class Program
{
    static void Main()
    {
        // Configuration
        var config = new Configuration
        {
            ClientId = "YOUR_CLIENT_ID",
            ClientSecret = "YOUR_CLIENT_SECRET"
        };

// API instances
        var signatureApi = new SignatureApi(config);
        var storageApi = new StorageApi(config);

// File paths
        string inputFilePath = "input.pdf";
        string outputFilePath = "output.pdf";

// Ensure file exists in storage (upload if needed)
        if (!storageApi.ObjectExists(new ObjectExistsRequest(new StorageExist
        {
            Path = inputFilePath,
            StorageName = null
        })).Exists)
        {
            using (var fileStream = File.OpenRead(inputFilePath))
            {
                storageApi.UploadFile(new UploadFileRequest(new UploadFile
                {
                    Path = inputFilePath,
                    File = fileStream
                }));
            }
        }

// Get list of signatures in the document
        var fileInfo = new FileInfo
        {
            FilePath = inputFilePath,
            StorageName = null,
            Password = null
        };
        var getSignaturesRequest = new GetSignaturesRequest(new GetSignaturesOptions
        {
            FileInfo = fileInfo
        });
        var signaturesResponse = signatureApi.GetSignatures(getSignaturesRequest);
        if (signaturesResponse.Signatures == null || signaturesResponse.Signatures.Count == 0)
        {
            Console.WriteLine("No signatures found.");
            return;
        }

// Choose first signature to edit
        var signatureToEdit = signaturesResponse.Signatures[0];
        string signatureId = signatureToEdit.SignatureId;

// Prepare new options (example: change text signature)
        var textOptions = new SignTextOptions
        {
            // Keep existing properties, modify as needed
            Text = "Edited Signature Text",
            Left = signatureToEdit.Left + 10,
            Top = signatureToEdit.Top + 10,
            Width = signatureToEdit.Width,
            Height = signatureToEdit.Height,
            Font = new SignatureFont
            {
                FontFamily = "Arial",
                FontSize = 12,
                Bold = true,
                Italic = false,
                Underline = false,
                Color = "FF0000"
            },
            // Preserve other required fields
            SignatureId = signatureId,
            PageNumber = signatureToEdit.PageNumber,
            // Set output file path
            OutputFilePath = outputFilePath
        };

var updateSignatureRequest = new UpdateSignatureRequest(new UpdateSignatureOptions
        {
            FileInfo = fileInfo,
            SignatureId = signatureId,
            Options = textOptions
        });

var updateResponse = signatureApi.UpdateSignature(updateSignatureRequest);

// Download updated file
        var downloadRequest = new DownloadFileRequest(new DownloadFile
        {
            Path = outputFilePath,
            StorageName = null
        });
        using (var downloadStream = storageApi.DownloadFile(downloadRequest))
        using (var fileStream = File.Create(outputFilePath))
        {
            downloadStream.CopyTo(fileStream);
        }

Console.WriteLine("Signature edited and saved to " + outputFilePath);
    }
}

curl -X POST "https://api.groupdocs.cloud/v2.0/oauth2/token" \
     -H "Content-Type: application/json" \
     -d '{
           "grant_type":"client_credentials",
           "client_id":"YOUR_CLIENT_ID",
           "client_secret":"YOUR_CLIENT_SECRET"
         }'

curl -X PUT "https://api.groupdocs.cloud/v2.0/storage/file/input.pdf" \
     -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
     -H "Content-Type: application/octet-stream" \
     --data-binary "@input.pdf"

curl -X POST "https://api.groupdocs.cloud/v2.0/signature/update" \
     -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{
           "fileInfo": {
               "filePath": "input.pdf"
           },
           "signatureId": "SIGNATURE_ID_FROM_GET",
           "options": {
               "text": "Edited Signature Text",
               "left": 120,
               "top": 150,
               "font": {
                   "fontFamily": "Arial",
                   "fontSize": 12,
                   "bold": true,
                   "color": "FF0000"
               },
               "outputFilePath": "output.pdf"
           }
         }'

curl -X GET "https://api.groupdocs.cloud/v2.0/storage/file/output.pdf" \
     -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
     -o output.pdf

var config = new Configuration { ClientId = "YOUR_CLIENT_ID", ClientSecret = "YOUR_CLIENT_SECRET" };

var signatureApi = new SignatureApi(config);
var storageApi = new StorageApi(config);

storageApi.UploadFile(new UploadFileRequest(new UploadFile { Path = inputFilePath, File = fileStream }));

var signaturesResponse = signatureApi.GetSignatures(getSignaturesRequest);
var signatureToEdit = signaturesResponse.Signatures[0];

using (var downloadStream = storageApi.DownloadFile(downloadRequest))

dotnet add package GroupDocs.signature-Cloud