There's currently no way to attach a file when commenting on, or posting an update to, a task (record) in a Table or Kanban view. We have to paste a link or put the file somewhere else on the board, so the context gets split up.
Request: Allow file attachments in task comments and updates, such as PDFs, Office documents and images. Show a preview or download link inline.
Use case: Our team tracks projects on a Kanban board. Partners and vendors send us files that move a task forward, like a revised document from a stakeholder or a vendor questionnaire. We want to attach the file directly to the update that mentions it , so the task history holds both the note and the file in one place.