How to Draw Lines on a PDF | Adobe, Preview, Edge & More

You can draw lines on any PDF by using the Line tool in the Comment or Markup menu, then clicking and dragging on the page.

Learning how to draw lines on a PDF is straightforward once you know where to find the line tool. Whether you need to mark up a contract, highlight a route on a map, or add a simple annotation, the process is similar across most editors. Below we cover the exact steps for the most popular desktop and browser-based PDF tools, along with the controls that let you customize line appearance. No matter which app you use, you can start drawing lines on your PDF in seconds.

Drawing Lines on a PDF: Methods for Every Platform

The core workflow is the same in almost every PDF editor: open the file, activate the Comment or Markup toolbar, select the Line or Shape tool, and drag across the page to create the line. Holding Shift while dragging forces the line to snap to 45‑degree angles (0°, 45°, 90°), making straight lines easy to create. In the sections below we walk through the specific button names and menu paths for the most widely used apps.

Adobe Acrobat (Desktop & Online)

Adobe Acrobat’s line‑drawing tool is part of the Comment workflow and works identically in the desktop app and in Acrobat online services. Step 1: Open the PDF and click Comment in the right‑hand toolbar. Step 2: On the Comment toolbar that appears, click Drawing Tools then select Line. Step 3: Click anywhere on the page and drag to draw. Hold Shift while dragging for a perfectly straight line. Step 4: Right‑click the line and choose Properties to change its color, thickness, opacity, or end caps. The line appears with small bounding‑box handles — you can drag them to resize or move the line. Press Delete to remove it.

macOS Preview & Microsoft Edge (Built‑In Viewers)

Free, built‑in PDF viewers can also draw lines, though they offer fewer formatting options than paid editors. In Preview (macOS): click the Markup toolbar icon (a pencil tip inside a circle), then choose the Shapes button and select Line. Drag to draw; hold Shift to constrain the line angle. Press Command+S to save. In Microsoft Edge (Windows & Mac): open the PDF, then click the Pen icon in the toolbar that appears at the top. Choose a line thickness and color, then draw freehand. (Edge does not have a dedicated straight‑line tool — use the Draw option and steady your hand, or draw a short line segment.) Save the document with Ctrl+S (Windows) or Command+S (Mac).

Other Editors (Smallpdf, Power PDF, Wondershare PDFelement)

Popular third‑party editors follow the same pattern. In Smallpdf (web or desktop): upload the PDF, use the Annotate tools, select Line, and draw. After editing, download the file. Tungsten Power PDF (version 4.0.0 and later) provides a dedicated line‑drawing tool with a Properties pane where you can set thickness, color, and line‑ending shapes (arrows, circles). Freehand lines can be corrected using the Eraser tool. Wondershare PDFelement offers three ways to add a line: underline selected text, insert a line shape from the Add Shape menu, or use the Pencil tool for freehand drawing. Right‑click any line to adjust color, opacity, and pixel width.

Which Line Properties Can You Adjust?

Once a line is drawn, most editors let you edit its appearance immediately. The table below shows the common controls and where to find them in the major tools.

Not all tools support every property. Preview and Edge, for example, lack opacity and end‑cap options — if you need those features, Adobe Acrobat or Power PDF are better choices.

Common Mistakes to Avoid

The most frequent error is confusing the freehand drawing tool with the line‑shape tool. Freehand is for sketching; the Line tool (often grouped under Shapes or Drawing Tools) creates a true geometric line that can be snapped straight with Shift. Another pitfall: in browser‑based editors like Smallpdf, lines are added as annotations rather than permanent edits — you must explicitly save or download the file to keep your changes. Finally, many desktop viewers (like Edge) do not let you adjust a line after it’s placed, so double‑check the position before saving.

Decision Guide: Which Method Should You Use?

The best tool depends on your workflow. The table below compares the most practical options across key factors.

For most users, the built‑in viewers (Preview on Mac, Edge on Windows) are enough for a quick line. If you need precise formatting — such as colored arrows or adjustable opacity — Adobe Acrobat’s line tool is the most reliable and feature‑rich choice.