✍️ PDF 签名Sign PDF
在 PDF 上添加手写签名：用鼠标或手指在签名板上书写、输入姓名生成签名，或上传签名照片并自动去除白底；拖动摆放到任意页面、调整大小，可放置多处，文件不上传。Add a handwritten signature to a PDF — draw it with a mouse or finger, type your name, or upload a photo of your signature with the white background removed. Drag it anywhere on any page, resize it, place it several times. Nothing is uploaded.
使用说明与常见问题How-to & FAQ
「PDF 签名」是什么？What is the Sign PDF tool?
在 PDF 上添加手写签名：用鼠标或手指在签名板上书写、输入姓名生成签名，或上传签名照片并自动去除白底；拖动摆放到任意页面、调整大小，可放置多处，文件不上传。Add a handwritten signature to a PDF — draw it with a mouse or finger, type your name, or upload a photo of your signature with the white background removed. Drag it anywhere on any page, resize it, place it several times. Nothing is uploaded.
如何使用「PDF 签名」？How do I use the Sign PDF tool?
在「PDF 签名」中，1. 选择或拖入 PDF（加密文件会先出现“密码”栏和“打开”按钮）。2. 在“签名方式”中选择：手写（在签名板上书写，可调颜色和笔粗，然后点“使用这个签名”）、输入文字（填写姓名、选字体后点“生成签名”）或上传签名图片。3. 用 ◀ ▶ 翻到目标页，拖动虚线框摆放、拖右下角圆点调整大小，点“放到此页”；每放一次，虚线框会自动下移，方便在同一页放下一处。4. 点“保存签名 PDF”下载。In the Sign PDF: 1. Choose or drop a PDF (for an encrypted file a Password field and an Open button appear first). 2. Pick a signature method: Draw (sign on the pad, adjust color and pen width, then click "Use this signature"), Type (enter your name, pick a font, click "Create signature") or Upload image. 3. Use ◀ ▶ to reach the page, drag the dashed box into place, resize it with the corner dot and click "Place on this page" — the box then moves down so the next placement does not overlap. 4. Click "Save signed PDF" to download.
这是具有法律效力的“数字签名”吗？Is this a legally binding digital signature?
不是。本工具添加的是可见的手写签名图片（电子签名的一种形式），不包含基于证书的加密数字签名（PAdES），无法证明文件签署后未被修改。合同等正式场景请确认对方接受这种签名方式，或使用 CA 证书签名服务。No. It adds a visible handwritten signature image (a simple electronic signature), not a certificate-based cryptographic digital signature (PAdES), so it can't prove the file wasn't altered afterwards. For contracts, check the other party accepts this, or use a certificate-based signing service.
手机上可以手写签名吗？Can I sign on a phone?
可以。签名板支持手指和触控笔书写，拖动虚线框摆放签名、拖右下角圆点调整大小，触屏同样可用。Yes. The pad works with fingers and styluses, and you can drag the dashed box to position the signature and drag the corner dot to resize it on touch screens too.
上传签名照片会有白底吗？Will an uploaded signature photo have a white background?
默认会自动去除接近白色的背景，让签名像真正写在纸上一样；如果效果不好（例如纸张偏灰），可以取消勾选或先用白纸、充足光线重新拍摄。By default near-white background is removed so the signature looks written on the page. If the paper looks grey, untick the option or retake the photo on white paper in good light.
可以在多个位置签名吗？Can I sign in several places?
可以。每次点击“放到此页”都会记录一处签名，可翻页继续放置，列表里可以删除任意一处，最后一次性保存。Yes. Each click on Place on this page records one signature; turn pages to add more, remove any from the list, then save once.
文件会上传到服务器吗？Are my files uploaded?
不会。PDF 在你的浏览器里用 pdf-lib / pdf.js 处理，文件不会离开你的设备，关闭页面后不留存任何数据。No. The PDF is processed in your browser with pdf-lib / pdf.js; files never leave your device and nothing is kept after you close the page.
「PDF 签名」免费吗？需要注册吗？Is the Sign PDF free? Do I need an account?
「PDF 签名」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Sign PDF is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.