Yes.
On any email you’re composing you can upload a file by either dragging the file onto the email or by clicking on the paperclip to open your computer's document finder to select the document from your computer.
Further Reading:
Is there a maximum amount of documents I can attach to an email?
Is there a limit to the size of files I can attach to an email?
Are documents and files attached to an email automatically added to a piece of work?