Boma allows you to link to a PDF in an email.
Create your email campaign and choose your template. Once you're in the email editor follow these instructions.
When using the insert link option from a body of text or a button, you can select ‘File Manager’ as an option which will take you to the file manager to upload your file.
Click on upload, browse to your PDF and click on open. Once it's loaded, click on insert.
This step allows you to include a link to the file, rather than the file itself.