Adding pdf attachments or other files to your emails can flag recipient email security, as well as slow down or stop your email send due to the increased size.
To optimise send success and user experience, we recommend you upload and host your file (e.g: upload to Google Docs, turning on public sharing), and link to it from an image, hyperlink or button in the email editor.
The additional benefit of this method is that it allows you to track engagement (clicks) with the file, to better understand how many of your contacts are interacting with it.
Used this way, you can also create a campaign to follow up with contacts who interact with the link, sending them subsequent content, relevant to their interests (see Campaign Triggers: Clicked).
You can also replicate a pdf in your ActivePipe account by using Image & Text panels.