diff --git a/src/hooks/filters/index.md b/src/hooks/filters/index.md
index 2938c95..e0146f3 100644
--- a/src/hooks/filters/index.md
+++ b/src/hooks/filters/index.md
@@ -19,6 +19,7 @@ Fluent Forms provides filter hooks that let you modify data and behavior. Filter
 | [User Registration](./user-registration/) | 10 | Modify user registration fields and roles |
 | [Webhook](./webhook/) | 5 | Modify webhook request arguments |
 | [Payment](./payment/) | 55 | Modify payment processing and gateway settings |
+| [PDF](./pdf/) | 7 | Control PDF add-on behaviour (public download links) |
 
 ## Quick Example
 
diff --git a/src/hooks/filters/pdf.md b/src/hooks/filters/pdf.md
index 5dee50c..b0129ed 100644
--- a/src/hooks/filters/pdf.md
+++ b/src/hooks/filters/pdf.md
@@ -1,6 +1,6 @@
 # PDF Filters
 
-<Badge type="tip" vertical="top" text="Filter Hooks" /> <Badge type="tip" vertical="top" text="Add-on" /> <Badge type="warning" vertical="top" text="6 Filters" />
+<Badge type="tip" vertical="top" text="Filter Hooks" /> <Badge type="tip" vertical="top" text="Add-on" /> <Badge type="warning" vertical="top" text="7 Filters" />
 
 Filters exposed by the **Fluent Forms PDF** add-on (`fluentforms-pdf`). Use these to customize mPDF configuration, the PDF body / CSS, template list, and watermark behavior. Source repo: `fluentforms-pdf`.
 
@@ -153,3 +153,32 @@ add_filter('fluentform/pdf_watermark_image_size', function ($value) {
 This filter is located in `fluentforms-pdf/Modules/FluentForms/Templates/TemplateManager.php` (line 182).
 
 </explain-block>
+
+<explain-block title="fluentform/pdf_public_download_ttl">
+
+Set a maximum age, in **seconds**, for a **public** PDF download link (the link produced by the `{pdf.download_link.<feed_id>.public}` smartcode and served by the unauthenticated `downloadPublic` endpoint).
+
+By default the value is `0`, which means **no expiry** — public links do not expire, preserving links already sent in notification emails. Return a positive number of seconds to expire links older than that. Links generated before a TTL was configured carry no timestamp and are never expired.
+
+**Parameters**
+
+- `$ttl` (int) Max age in **seconds**; `0` disables expiry (default)
+- `$feedId` (int) PDF feed ID
+- `$submissionId` (int) Submission ID
+
+**Usage**
+
+```php
+// Expire public PDF links 30 days after they are generated.
+add_filter('fluentform/pdf_public_download_ttl', function ($ttl, $feedId, $submissionId) {
+    return 30 * DAY_IN_SECONDS;
+}, 10, 3);
+```
+
+**Reference**
+
+`apply_filters('fluentform/pdf_public_download_ttl', 0, $feedId, $submissionId);`
+
+This filter is located in `fluentforms-pdf/Modules/FluentForms/FluentFormsIntegration.php` -> downloadPublic()
+
+</explain-block>