Attachment
An email attachment in email marketing refers to any file that is appended as a supplement to the main message of your email.
An attachment is a file sent with an email message, such as a PDF, image, or ZIP.
Definition and examples
An attachment is any file you include with an email (for example, PDFs, images, spreadsheets). Attachments add detail or resources that don’t fit in the body copy.
Why it matters
It matters because attachments affect trust, deliverability, and usability all at once. The wrong file type or file size can create friction before the recipient even gets to the message.
Examples / Use cases
PDF invoice or receipt accompanying a transactional email. One-pager PDF for a product update sent to opted-in customers. Compressed ZIP when multiple small files are required.
Common mistakes
A common mistake is attaching a file when a link would work better. Large or unnecessary attachments slow the experience down and can trigger security concerns.
Related terms
Key takeaways
Attachments are useful but can impact deliverability and security
Keep sizes small, use safe formats, and link to heavy assets
Always explain attachments and use descriptive filenames