Add Signature to PDF
Place a signature image on a selected PDF page
Add Signature to PDF — what it does
Place a signature image onto a chosen page of a PDF, controlling its width, opacity and position as percentages of the page. Percentage positioning is what makes it predictable across page sizes: the same settings land in the same visual place on A4 and Letter alike.
When this tool helps
- Signing a contract or form that arrived as a PDF without printing and scanning it.
- Adding an approval signature to an internal document before circulating it.
- Placing an initial or mark on a specific page of a longer agreement.
How to use it
- Choose the PDF file.
- Select the signature image, ideally a PNG with a transparent background.
- Set the target page, width, opacity and position.
- Process and download the signed PDF.
Accuracy, limits, and good practice
- Sign on white paper in good light, photograph it, and remove the background so the signature does not arrive inside a white box.
- Slightly reduced opacity blends a signature more naturally onto the page, mimicking real ink density.
- This places an image; it is not a cryptographic digital signature. Where legal non-repudiation is required, use a certificate-based e-signature service.
Frequently asked questions
Is an image signature legally binding?
In many jurisdictions an electronic signature is valid, but requirements vary by document type and country. Check before relying on it for anything significant.
What image format works best?
A PNG with a transparent background. A JPEG carries a white rectangle that will sit visibly on top of the page.
Can I sign several pages?
One page per pass. Run the tool again on the result for each additional page that needs a signature.
Related tools on this site
- Rotate PDF — Rotate every page by 90, 180, or 270 degrees
- Images to PDF — Combine JPG, PNG, and WebP images into one PDF
- Add Image Stamp to PDF — Apply a logo or stamp image to every PDF page
Everything above runs inside this page. Add Signature to PDF needs no account, no upload, and no server round trip — close the tab and nothing is left behind.
PDF 加入簽名能做什麼
把簽名圖片放到 PDF 的指定頁面，寬度、透明度與位置都以頁面百分比控制。用百分比定位，跨頁面尺寸才可預測：同一組設定在 A4 與 Letter 上會落在相同的視覺位置。
什麼時候用得上
- 簽署以 PDF 寄來的合約或表單，不必列印再掃描。
- 在內部文件流轉前加上核准簽名。
- 在較長協議的特定頁面加上簽名或縮寫。
使用步驟
- 選擇 PDF 檔案。
- 選擇簽名圖片，建議使用透明背景的 PNG。
- 設定目標頁、寬度、透明度與位置。
- 執行處理並下載簽署後的 PDF。
精確度、限制與實務建議
- 在光線良好處於白紙上簽名、拍照後去背，簽名才不會裝在一個白色方塊裡送出去。
- 透明度略降能讓簽名更自然地融入頁面，接近真實墨水的濃度。
- 這裡放的是圖片，不是密碼學數位簽章。需要法律上不可否認性時，請使用憑證式電子簽章服務。
常見問題
圖片簽名有法律效力嗎？
許多法域承認電子簽名，但要求依文件類型與國家而異。重要文件請先確認再使用。
哪種圖片格式最好？
透明背景的 PNG。JPEG 會帶著白色矩形，明顯壓在頁面上。
可以簽好幾頁嗎？
一次一頁。需要多頁簽名時，把結果再送回工具逐頁處理。
本站相關工具
- 旋轉 PDF — 將所有頁面旋轉 90、180 或 270 度
- 圖片轉 PDF — 將 JPG、PNG、WebP 圖片合併成一個 PDF
- PDF 加入圖片印章 — 在每一頁 PDF 加入 Logo 或印章圖片
以上步驟全部在這個頁面內完成，PDF 加入簽名 不需要註冊、不上傳檔案、也不經過伺服器，關閉分頁後不會留下任何資料。