PDF 工具

如何使用在线工具签署 PDF 文档

已更新:八月 20, 2025

PDF 文件是存储信息、保留文档布局以及字体和图像的优秀工具。这是它们至今仍然如此受欢迎的主要原因之一。在现代社会中，许多人远程工作。填写和签署表格、发送文件以及处理文档只是企业每日需要完成的一些主要活动。其中一个主要活动是以 PDF 文档代替纸质文件进行签署。随着公司寻找签署协议和合同以及在线分享 PDF 表格的方法，数字签名变得必不可少。本文将列出用于 PDF 文档的在线签署工具。

IronPDF — 使用 C# 库签署 PDF

IronPDF 是适用于使用 C# 的桌面计算机的所有 PDF 相关任务的理想工具。它允许开发人员添加签名、填写和签署 PDF 文档、加密安全的 PDF 表单，甚至添加您的签名图像。 IronPDF 涵盖了签署 PDF 文档所需的所有方面。

开发人员通常询问如何使用 IronPDF 和 C# 以编程方式向 PDF 添加签名。通常这对不同的开发人员来说意味着不同的事情：

从图像文件中向现有 PDF 文件添加图形数字签名图像。
加密签署 PDF 以确保它未被篡改。
加密签署 PDF 并添加人工手写签名图标。

第一种方法是在现有 PDF 页上加盖签名 PNG。它可以用于公司印章或签名。支持不透明度。整个过程仅需几行代码。

// Open an existing PDF document or create a new one
PdfDocument pdf = PdfDocument.FromFile(@"C:\Path\To\ASPX to PDF.pdf");

// Prepare a signature stamp with specified dimensions and position
var signatureStamp = new HtmlStamp() 
{ 
    HTML = "<img src='signature.png' />", 
    Width = 150, 
    Height = 50, 
    Bottom = 300, 
    Left = 85, 
    ZIndex = HtmlStamp.StampLayer.OnTopOfExistingPDFContent 
};

// Apply the stamp to the first page of the PDF
pdf.StampHTML(signatureStamp, 1);

// Save the updated PDF file
pdf.SaveAs(@"C:\Path\To\ASPX to PDF.pdf");

// Open an existing PDF document or create a new one
PdfDocument pdf = PdfDocument.FromFile(@"C:\Path\To\ASPX to PDF.pdf");

// Prepare a signature stamp with specified dimensions and position
var signatureStamp = new HtmlStamp() 
{ 
    HTML = "<img src='signature.png' />", 
    Width = 150, 
    Height = 50, 
    Bottom = 300, 
    Left = 85, 
    ZIndex = HtmlStamp.StampLayer.OnTopOfExistingPDFContent 
};

// Apply the stamp to the first page of the PDF
pdf.StampHTML(signatureStamp, 1);

// Save the updated PDF file
pdf.SaveAs(@"C:\Path\To\ASPX to PDF.pdf");

' Open an existing PDF document or create a new one
Dim pdf As PdfDocument = PdfDocument.FromFile("C:\Path\To\ASPX to PDF.pdf")

' Prepare a signature stamp with specified dimensions and position
Dim signatureStamp = New HtmlStamp() With {
	.HTML = "<img src='signature.png' />",
	.Width = 150,
	.Height = 50,
	.Bottom = 300,
	.Left = 85,
	.ZIndex = HtmlStamp.StampLayer.OnTopOfExistingPDFContent
}

' Apply the stamp to the first page of the PDF
pdf.StampHTML(signatureStamp, 1)

' Save the updated PDF file
pdf.SaveAs("C:\Path\To\ASPX to PDF.pdf")

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以下代码使用 .pfx 或 .p12 X509Certificate2 数字证书加密签署 PDF，这可以通过一行代码轻松生成。

// "123456" represents the password for the signature certificate
new IronPdf.PdfSignature("CertificateFile.p12", "123456").SignPdfFile("ASPX to PDF.pdf");

// "123456" represents the password for the signature certificate
new IronPdf.PdfSignature("CertificateFile.p12", "123456").SignPdfFile("ASPX to PDF.pdf");

' "123456" represents the password for the signature certificate
Call (New IronPdf.PdfSignature("CertificateFile.p12", "123456")).SignPdfFile("ASPX to PDF.pdf")

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这一更高级的示例允许 .pfx / .p12 X509Certificate2 数字 ID 签署方法与手写签名扫描结合使用。

// Create a new PDF signature using a digital certificate
var signature = new IronPdf.PdfSignature("Iron.pfx", "123456");

// Render some content to PDF
PdfDocument doc = Renderer.RenderHtmlAsPdf("<h1>Testing 2048 bit digital security</h1>");

// Optional signing options and a handwritten signature graphic
signature.SigningContact = "support@ironsoftware.com";
signature.SigningLocation = "Chicago, USA";
signature.SigningReason = "To show how to sign a PDF";

// Load and apply a signature image to the document
signature.LoadSignatureImageFromFile("handwriting.png");

// Sign the PDF with the digital certificate and signature image
doc.SignPdfWithDigitalSignature(signature);

// Save the signed PDF document
doc.SaveAs("ASPX to PDF.pdf");

// Create a new PDF signature using a digital certificate
var signature = new IronPdf.PdfSignature("Iron.pfx", "123456");

// Render some content to PDF
PdfDocument doc = Renderer.RenderHtmlAsPdf("<h1>Testing 2048 bit digital security</h1>");

// Optional signing options and a handwritten signature graphic
signature.SigningContact = "support@ironsoftware.com";
signature.SigningLocation = "Chicago, USA";
signature.SigningReason = "To show how to sign a PDF";

// Load and apply a signature image to the document
signature.LoadSignatureImageFromFile("handwriting.png");

// Sign the PDF with the digital certificate and signature image
doc.SignPdfWithDigitalSignature(signature);

// Save the signed PDF document
doc.SaveAs("ASPX to PDF.pdf");

' Create a new PDF signature using a digital certificate
Dim signature = New IronPdf.PdfSignature("Iron.pfx", "123456")

' Render some content to PDF
Dim doc As PdfDocument = Renderer.RenderHtmlAsPdf("<h1>Testing 2048 bit digital security</h1>")

' Optional signing options and a handwritten signature graphic
signature.SigningContact = "support@ironsoftware.com"
signature.SigningLocation = "Chicago, USA"
signature.SigningReason = "To show how to sign a PDF"

' Load and apply a signature image to the document
signature.LoadSignatureImageFromFile("handwriting.png")

' Sign the PDF with the digital certificate and signature image
doc.SignPdfWithDigitalSignature(signature)

' Save the signed PDF document
doc.SaveAs("ASPX to PDF.pdf")

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使用 C# 表单打开 PDF 文档：