Link annotations in Link tag

Link annotations in Link tag is a PDF/UA check in PAC, the free PDF Accessibility Checker. It fails when a link's clickable area, called a link annotation, isn't placed inside a Link tag in the document's structure. PDF/UA, the ISO standard for accessible PDFs, also requires every link annotation to carry a short text description, so this page covers both requirements.

What this means

A working, accessible link in a PDF has three parts:

1. The visible link text on the page, such as "Apply for a building permit".
2. The link annotation, an invisible clickable rectangle that holds the web address or the page it jumps to.
3. A Link tag in the tag tree (the document's hidden structure) that holds both: the tagged link text and a pointer to the annotation, called an object reference or OBJR.

When the annotation isn't inside a Link tag, assistive technology may not connect the text to the link, or may not find the link at all. PAC shows the check among its annotation results, which is why people search for it as "PDF/UA annotations".

The second requirement is a description in the annotation's Contents entry, such as "Apply for a building permit on the county website". It gives assistive technology a name for the link even when the link text is a bare web address.

Links usually end up untagged when:

• they were added in Acrobat after the file was tagged;
• a tool turned web addresses in the text into links without tagging them;
• pages were combined from different files and the links lost their tags;
• the file was exported with tagging turned off, or printed to PDF.

Why it matters

Screen reader users often bring up a list of all the links in a document to move around it. Untagged links can be missing from that list, announced with no text, or read out as a long web address. That undermines WCAG 2.1 success criteria 1.3.1 Info and Relationships, 2.4.4 Link Purpose (In Context) and 4.1.2 Name, Role, Value. Keyboard users are affected too, because the order they tab through links follows the tags.

How to fix it in Acrobat Pro and re-check in PAC

Fix it in the source file

Links made in the source document are tagged correctly when you export with tags, and they survive the next update:

• Word: insert links with Insert > Link and type meaningful display text, such as "Apply for a building permit", instead of pasting a bare web address. Export with File > Save As > PDF with Document structure tags for accessibility turned on. Microsoft documents that Word puts each text link in a Link tag with its OBJR.
• InDesign: create links in the Hyperlinks panel, and turn on Create Tagged PDF and Hyperlinks when you export.
• Any app: avoid adding or editing links in Acrobat after export. Make the change in the source and export again.

Fix it automatically with Includoc

Includoc fixes both parts automatically. For every link, we create a Link tag that holds the link text and the link annotation together, and we write a description for each link from its visible text and destination.

What a machine can't fully judge is whether the link text makes sense on its own. Text such as "click here" or "read more" is a wording problem, not a tagging problem. Our AI suggests a clearer description for each unclear link, but we can't change the visible words in a PDF, so fix those in the source when you can.

Standards

Related errors

• Tagged annotations – Failed: Acrobat's version of this problem, which also covers comments and stamps.
• Annotation has alt text: descriptions for comments, stamps and other annotations.

For the full workflow, see How to make a PDF accessible, or check a PDF free to find every untagged link.