How to Sign a PDF Online

Mac: using Preview

Open the PDF in Preview, click the markup toolbar icon, choose the signature tool, and select a signature you've already created (or create one there). Since you already have a clean PNG from SignScribe, you can also just drag-and-drop the downloaded image straight onto the page and resize it.

Windows: using a browser PDF viewer

Chrome and Edge's built-in PDF viewers support basic annotation tools, though image insertion support varies by browser version. If your browser's viewer doesn't support inserting images directly, most free PDF editors (many run entirely client-side, similar to SignScribe) let you drag your downloaded PNG onto the page.

Why sign a PDF instead of printing and scanning?

Printing a document, signing it by hand, scanning it back in, and emailing the result used to be the default way to handle paperwork — and it's still surprisingly common. But it costs real time, wastes paper, and often produces a crooked, low-resolution scan that looks unprofessional next to a clean digital original. Signing directly in the PDF, with a signature image you've already prepared once and can reuse indefinitely, takes under a minute and produces a document that looks exactly as sharp as the original.

Method comparison: which approach fits your situation?

Detailed walkthrough: Mac Preview

1. Open the PDF by double-clicking it, which typically opens in Preview by default on macOS.
2. Click the markup toolbar icon (it looks like a pen tip inside a circle) near the top-right of the window.
3. Click the signature icon, then choose "Create Signature" if this is your first time, or select a saved one.
4. Alternatively, skip Preview's built-in signature creator entirely: drag your downloaded transparent PNG from SignScribe straight onto the document.
5. Click and drag the signature into position, use the corner handles to resize it proportionally, then export or save the file.

Detailed walkthrough: Windows and browser viewers

1. Open the PDF in Chrome or Edge by dragging it into a browser tab, or right-click the file and choose "Open with" your browser.
2. Look for an annotation or "Fill & Sign" toolbar at the top of the built-in viewer.
3. If your browser version supports image insertion, upload your saved signature PNG directly and position it on the page.
4. If it doesn't, use a free client-side PDF editor (many process everything locally in your browser, similar in spirit to SignScribe) to add the image instead.
5. Download the completed file once the signature is placed and sized correctly.

Signing on a phone or tablet

Most mobile PDF apps — including the Files app and Adobe Acrobat Reader on both iOS and Android — include a built-in signature tool that lets you draw directly with your finger. If you'd rather reuse a signature you've already perfected, export your SignScribe signature as a PNG, save it to your device's photo library, then insert it as an image inside the PDF app the same way you would on desktop. This is especially useful if you've spent time getting a typed or drawn signature to look exactly right and don't want to redraw it clumsily with a fingertip every time.

Keeping your signed PDF secure

Once a document is signed, a few habits keep it trustworthy: save the final signed version as a new file rather than overwriting your blank template, avoid re-editing a signed PDF (which can raise authenticity questions later), and if the document matters legally, keep a dated copy of the email or platform confirmation showing when and how it was sent or countersigned.