How to attach an Email to another Email in Outlook Sometimes you want to attach an email to another email as proof to your current mail, in this situation you just cant copy and paste the mail chain in the mail body. Lets see the correct way of doing that. Click on new mail, new window will be opened/Reply to the existing mail In the tool bar click on message tab, under it you will find attach file, attach item, signature etc. Click on attach item, from the drop down menu select Outlook item. A dialog box will appear, in that browse and select the mail which you want to attach. You can even attach business card, for that in 3rd step select attach Business Card instead of Outlook item.