In WordPress, an attachment refers to any file that is uploaded to a post or page, including images, videos, audio files, and documents.
When an attachment is uploaded, WordPress automatically creates an attachment page for it, which is a separate page that displays information about the attachment, such as the title, caption, description, and metadata.
Attachments can be inserted into posts or pages using the media library, which provides a user-friendly interface for managing and selecting files.
Attachment can be an image, video, gif, pdf, or any supporting documents uploaded into any posts or pages.