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Top 5 Free PDF Highlighter App for iPad and iPhone in 2023

Being able to alter a PDF document used to be difficult, as the Portable Document Format (PDF) was made to retain original file formatting. Hence, editing it can prove quite difficult. To make any changes, you would need to convert to other editable document formats.

However, with PDF editing apps for iPad and iPhone, you can now execute several annotation functions. One of these is highlighting. Here outlined are the top PDF highlighter apps.

Top 5 PDF Highlighter Apps for iPad and iPhone

The best PDF highlighter apps for iPad include:

1)   UPDF

UPDF for iOS App is one of the apps available on the iPad and iPhone for highlighting the content of a PDF document. There are multiple highlighting tools for you to draw free-hand markups, straight lines, add magnifier to texts etc.

However, it does much more than enable highlights. Several provisions are available for viewing, managing, and annotating PDF files. In the area of annotation, users can add comments to any section of a PDF document. They can insert, edit, delete, rearrange, and move texts and images. They can also crop or reduce the size of existing ones within the PDF file.

pdf highlighter app - updf

You aren't limited to just tampering with an already created PDF as you get the tools to get a new PDF. In the new PDF document, you can insert new texts, images, forms, fields, and signatures. One of the most fascinating provisions of UPDF is the scan to PDF feature. You can scan any paper documents and save them as a PDF document.

2)   pdfFiller

pdfFiller is another software that enables users to highlight PDF on iPad. Its highlighting tool is fast, effective, and highly responsive. It is also available in multiple thickness and colors.

pdf highlighter ipad

The pdfFiller app itself is, however, a comprehensive PDF manager and editor. It enables documents signing and filling of forms using multiple methods. One innovative addition to all of these is that you can export these edits and annotations across multiple PDF files.

Furthermore, pdfFiller allows for collaboration as users can fill in their comments on any section of the document and share those comments with others. Finally, the app prioritizes the use of cloud storage. This makes it possible for all activities you carry out to sync almost immediately across devices.

3)    PDF Expert

PDF Expert is one of the best apps users go for when they want to highlight PDFs on iPad. It is highly preferred among both personal and corporate users as a result of its quick software and full range of features.

highlight pdf on ipad

The highlight function is a part of a range of editing tools that make it possible to manage their PDFs as they want. For instance, users can protect sensitive information on their PDFs by redacting sections. The editing function provides users with easy navigation of the PDF content through the outline creation feature. Users can also input hyperlinks.

Then, apart from being able to highlight seamlessly, you also get a reading experience that is top-notch. For instance, there is the multi-file view option that allows you to view more than one document at a single time. This will come in handy when you need to compare documents at the same time.

Furthermore, the app allows for flexibility as you can view your documents in whatever themes you desire.

4)   Small PDF

Smallpdf would easily rank on the list of best apps to highlight PDF on iPad. The highlight function is effortless and customizable. Then after putting the highlight mark on an area, you can further edit it as you wish.

how to highlight pdf on ipad

However, highlighting is just one of the very few unique functions that SmallPDF is optimized for. There is the form-filling function with which users can insert their information in forms that are sent in the PDF file format. In addition, the app contains tools with which users can create these forms from scratch.

Furthermore, you can append signatures on the PDF either by scanning or freehand drawing. Once you have provided your signature the first time, you can use the auto-fill tool to insert it anytime you need to append your signature.

You can also edit, delete, or add texts and images, and to make notes across the PDF document. If the need is to create a PDF document, SmallPDF is also the app to use. You can generate a PDF document by using the "Create" function within the app and filling in the content.

You can also convert an existing file from one format to PDF. Finally, you can scan documents to create a new file. The OCR tech in SmallPDF will help make the scanned images editable.

5)   Adobe Acrobat Pro

The Adobe Acrobat Pro is a comprehensive PDF tool that enables users to edit, create annotations, and protect their PDF files.

Among the available features is "Collaboration" which makes it possible for several persons to work on the same document at the same time. The owner of the document can send the PDF file to multiple recipients at once, requesting edits from each of them.

highlight pdf on iphone

The "Collaboration" tool makes it possible for multiple contributors to work on the same PDF document. The 'Send for Review' command dispatches the document to collaborators with just a few clicks. These collaborators can carry out various actions on the document, including using the 'Sticky Note' to make comments.  Similarly, users can send personalized invites for signatures.

How to Highlight PDF on iPad

Highlighting a PDF file on iPad using any app is straightforward. However, since the process might not exactly be the same across all PDF highlighter apps, we will be selecting the UPDF app. UPDF presents the best highlighting experience on the iPad. You can make use of your bare fingers or operate with your Apple Pencil if you have access to one.

The process includes:

  1. Open the PDF document that contains the texts you want to highlight.
  2. On the document's page, you find a row of icons at the bottom of the page. These icons look like pencils. Pick the Highlighter icon, after which an array of colors pops up on your screen. Choose the color you want your highlights to be in.
  3. Next, go to the section of the document you wish to highlight and select the relevant lines.
  4. The areas will immediately be highlighted in your desired colors.
best app to highlight pdf on ipad

How to Highlight PDF on iPhone

Highlighting a PDF on the iPhone can be just as seamless as you get on the iPad. The only downside is that you can't use the Apple Pencil. Then, the screen is remarkably limited to navigating the different highlighter features. Nonetheless, if you use the right PDF highlighter apps, you should have fewer of these problems. Such an app is UPDF.

Outlined here is the process to highlight your PDF on the iPhone:

  1. After opening the document, go to the section that you wish to highlight.
  2. Select this paragraph or section by press-clicking one point, preferably the start of the section. Here, you place your finger on this point and hold it down till the area gets marked. Without removing your finger, gently extend this marked area to the other parts of the section to be highlighted.
  3. Immediately you lift your fingers, an array of options will pop up, including such commands as "Copy" and "Select All". Click on the "Highlight" at the end of this list of options.
pdf highlighter app

Immediately, the marked area will become highlighted.


One of the key functions you can perform on a PDF file is to highlight sections of it. Highlighting will enable you to quickly reach a portion of the document that you want to visit later. However, not all PDF reader apps are great at this. Here, we have outlined the best for you to make a choice - UPDF.