PDF attachments are not necessarily considered spam by default, but they can potentially trigger spam filters if they are included in a large number of unsolicited emails, or if the content of the PDF is flagged as suspicious or malicious by spam filters.
To avoid triggering spam filters, it’s important to ensure that your email is targeted and relevant to the recipient, and that the content of the PDF is high-quality and informative.
You can also consider using a service like Mailchimp to send your emails, as these services have measures in place to prevent emails from being flagged as spam. Other Services such as LandingDoc provide a way to turn a PDF into a link, so that the PDF is not actually part of the message as an attachment.
In general, it’s a good idea to follow best practices for email marketing, such as obtaining permission from recipients before sending them emails, and providing a clear and easy way for recipients to opt-out of future emails. By following these guidelines and ensuring that your emails are targeted and relevant, you can help prevent them from being flagged as spam.