PDF Fundamentals

This page provides an overview of common PDF tags. Creating, editing and managing tags is addressed in the PDF Remediation guide.

Document Tag

The Document tag should always be the first tag in a PDF, the "root" of the tag tree. All other tags are nested within the Document tag.

Tag	Name	Purpose	Example
<Document>	Document	The main document tag, contains all other tags

Containers

Containers are optional tags that group other tags or content.

Tag	Name	Purpose	Example
<Part>	Part	Contains a large portion of the document, like a chapter
<Art>	Article	Article within a document
<Sect>	Section	Contains a smaller part of a document, like pull a quote
<Div>	Content Division	Generic container
<Span>	Span	Generic inline container, e.g., for stylized text within a sentence

Headings

Headings provide the document hierarchy.

Tag	Name	Purpose	Example
<H1>	Heading 1	Document heading
<H2>	Heading 2	Second-level headings, like chapter titles
<H3> - <H6>	Heading 3 - Heading 6	Subheadings

Text

Tag	Name	Purpose	Example
<P>	Paragraph	Body text
<BlockQuote>	Block Quote	Long quote in its own paragraph
<Caption>	Caption	Figure or table caption, placed above or below a figure or table

Links

Tag	Name	Purpose	Example
<Link>	Link	External link (webpage, email); contains a Link - OBJR tag
OBJR	Object Reference	Required for interactive elements, including links and forms.

Images

Images embedded in a PDF are represented by the following tags. For each, descriptive alternative text must be provided in the tag's properties.

Tag	Name	Purpose	Example
<Figure>	Figure	Image or graphic
<Formula>	Formula	Mathematical or chemical formula

Lists

Tag	Name	Purpose	Example
<L>	List	Main tag for a list
<LI>	List Item	Individual list items, nested under a List tag
<Lbl>	Label	Nested under a List Item to identify its decorator (a bullet for unordered lists, a number for an ordered list, etc.)
<LBody>	List Item Body	Contains a List Item's actual content, nested under a List Item

Table of Contents

Tag	Name	Purpose	Example
<TOC>	Table of Contents	Main tag for a table of contents
<TOCI>	Table of Contents Item	Table of contents entry, nested within a TOC; contains a <Reference> tag
<Reference>	Reference	Internal link (TOC, footnote)

Tables

Tables provide structure for tabular data.

Tag	Name	Purpose	Example
<Table>	Table	Main tag for a data table
<TR>	Table Row	Table row, nested within a Table
<TH>	Table Header	Table row or column header, nested within a Table Row
<TD>	Table Data	Table data cell, nested within a Table Row

Forms

Form tags are used for interactive forms.

Tag	Name	Purpose	Example
<Form>	Form	Fillable form elements (checkboxes, text inputs, etc.); contains the element's OBJR tag. Form tags are typically nested within a paragraph tag containing the form element's text label.

Artifacts

When content is marked as an artifact, it is hidden from assistive technology. Common artifacts include decorative images, repeated header or footer content, page numbers and placeholders for form fields. Artifacts are not visible in the tag tree.