OmniDocAnnotate PDF on Mac: Free Tools and Options
Compare the main ways to annotate a PDF on a Mac, from built-in viewers to desktop editors, and see which one fits highlights, text edits, signing or page work.
If you need to annotate a PDF on a Mac, the job is usually one of a few things: highlight a passage, leave a comment, fix a typo, sign a form, or rearrange pages before sending the file back. Each of these needs a different kind of tool, and picking the wrong one often means discovering a missing feature halfway through a review.
This guide compares the common ways to annotate a PDF on a Mac, from built-in viewers to online services and desktop editors. OmniDoc's PDF editor covers text edits, signing, form filling and page work, so it is the focus for those jobs. For highlights and comments, you will see where another method makes more sense.
You will get a short answer, a comparison of approaches, a guide to choosing one, and steps for doing the editing work in OmniDoc.
How should you annotate a PDF on Mac? The short answer
Use the PDF viewer built into macOS for highlights and comments, and use the OmniDoc macOS client when you need to change text, sign, fill a form or work with pages.
| Your situation | What to do | Why |
|---|---|---|
| You only need highlights and comments | Use the PDF viewer built into macOS | It is already on your Mac and suits quick review |
| You must fix a typo or change a sentence | Edit the paragraph text in the OmniDoc PDF editor | Text is edited in place, not covered with a box |
| You need to sign or fill a form | Use the signing and form tools in the OmniDoc PDF editor | Both are listed features of the editor |
| The PDF is a scan and text will not select | Run OCR in the OmniDoc PDF editor, then check the result | OCR adds a text layer to scanned pages |
| You need to reorder, merge or split pages | Use page operations in the OmniDoc PDF editor | Insert, delete, rotate, reorder, merge and split are supported |
How each approach works
The PDF viewer built into macOS
This viewer opens PDFs and lets you highlight text, add notes and place simple shapes. It suits quick reading and comment-style review, and it does not require installing anything. Its markup tools are generally aimed at marking a document rather than changing its wording, so if you need to correct a sentence, you will need an editor.
Browser PDF viewers
Opening a PDF in a browser tab is common for quick reading. Some browsers offer highlights or notes in their viewer toolbar. Support varies by browser and by file, so before you send a marked-up file, confirm that your marks are saved into the PDF and still appear when someone else opens it.
Online markup tools
Online markup tools let you upload a PDF to a website, add marks, and download the result. They suit occasional use, especially on a machine where you cannot install software. The trade-offs are that you upload the document to a third party, so read the privacy terms first, and some plans add watermarks or limit file size.
Desktop PDF editors
General-purpose desktop editors include markup, text editing, signing and page tools in one program. They suit people who edit PDFs often. Full-featured editors usually come with a license fee, and their menus can take time to learn.
The OmniDoc macOS desktop client
Download the desktop client for macOS from download.omnidoc.top. Its PDF editor lets you edit paragraph text in place, sign, fill forms, redact, run OCR on scanned PDFs, insert, delete, rotate, reorder, merge and split pages, compare two PDFs, and export to Word, Excel or PowerPoint. It suits text corrections, signatures, form work and page changes in one app. The product facts do not list highlight or sticky-note markup, so for comment-style review, pair it with the built-in viewer.
📊 At a glance
| Approach | Highlights and notes | Edits existing text | Signing | Page operations |
|---|---|---|---|---|
| PDF viewer built into macOS | Yes | Usually no | Often yes | Limited |
| Browser PDF viewers | Varies by browser | Usually no | Varies | Usually no |
| Online markup tools | Yes | Varies | Varies | Varies |
| Desktop PDF editors | Yes | Yes | Yes | Yes |
| OmniDoc macOS client | Use the built-in viewer | Yes, in place | Yes | Yes, including merge and split |
🎯 Which approach fits you?
If you only need to highlight and leave comments
The PDF viewer built into macOS is usually enough. Mark the passages, add notes, and send the file on. You do not need to install anything for this.
If you need to correct wording or a number
Use the OmniDoc PDF editor to edit the paragraph text in place. Check the changed line against the original, since a small edit can shift the surrounding text.
If you need to sign a contract or fill a form
Use the signing and form tools in the OmniDoc PDF editor. If you need others to sign, OmniDoc also offers sign requests, where you send a PDF for signing online.
If your PDF is a scan
Scanned pages are images, so text will not select. Run OCR in the OmniDoc PDF editor, then review the recognized text, since OCR can misread characters, especially in names and figures.
If you reorganize pages before review
Use the page operations in the OmniDoc PDF editor to insert, delete, rotate, reorder, merge or split pages. Then export to Word if a colleague needs an editable copy.
Editing and signing a PDF on Mac in OmniDoc
- Download the macOS desktop client from download.omnidoc.top and open it.
- Open your PDF in the PDF editor.
- For a typo or wording change, edit the paragraph text in place and compare it with the original.
- If text will not select, the page is probably a scan. Run OCR, then check the recognized text.
- To sign or fill a form, use the signing and form tools, then save or export the PDF.
- For page changes, use the page operations, and use export to Word, Excel or PowerPoint if you need an editable copy.
❓ FAQ
1. Can I annotate a PDF on Mac for free?
Yes. The PDF viewer built into macOS handles highlights and notes without an extra download. If you choose an online tool instead, check its file size limits, watermarks and whether your marks stay in the saved file.
2. Does OmniDoc add highlights and sticky notes?
The product facts for the PDF editor list text edits, signing, form filling, redaction, page operations, OCR, comparison and export, but not highlights or comments. For those marks, use the viewer built into macOS.
3. Why won't my scanned PDF let me select text?
Text in a scan is an image, so there is no text layer to select. Run OCR to add one, then check the result before you rely on it. To test a file, try selecting a line of text: if nothing highlights, the page is likely a scan.
4. Can I compare two versions of a marked-up PDF?
Yes. The OmniDoc PDF editor can compare two PDFs, which helps you see what changed between a draft and a revised copy.
📝 Summary
Annotating a PDF on a Mac comes down to matching the tool to the job. Use the viewer built into macOS for highlights and comments, and use the OmniDoc macOS client for text edits, signatures and page work. Check any online tool for limits and watermarks before you rely on it.
