From the Knowledgebase

Gutenberg Editor and PDF Embedder

The PDF Embedder plugin v.4.0 for the free, Premium, and Secure versions work with WordPress v.5.0 and Gutenberg Editor plugin v.4.6.1.

Open the Common Blocks menu and select the PDF Embedder:

An element will be inserted into the page / post content. Click on the generated link to navigate to the Media Library:

Select or Upload your PDF and click the "Select" button. The element will now display the URL to the document you are embedding:

With the block element selected as per screenshot above, you can also customise the specific height, width, toolbar location and behavior from the menu to the right for that particular embed. If this is left blank, the defaults configured in the plugin Settings tab will be used instead.

The plugin also works with the Classic Editor block with the Add Media button to embed the PDF normally—this is also the best way to insert a thumbnail image and have it linked to the PDF's attachment page, or use the Shortcode block to copy and paste the PDF's URL into the shortcode added manually [pdf-embedder url="path-to-pdf"]: