Drag open Excel or Word file into Mail as an attachment
There are alternvative way(s). One of them being open Spotlight (⌘ + Space), enter first letters of file name and drag it from the results list to email.
If you haven't started to write e-mail then 'Share' inside Excel can be used. There are two possible approaches (1) click on icon in right-upper labeled 'Share' &gt; click 'Send a Copy' &gt; change 'Send as' if needed (default Excel Workbook, alternative is PDF) and click 'Email as Attachment' (or on icon next to it which allows to send copy to other apps), or, (2) from menubar select File &gt; Share &gt; Send Workbook (or Send PDF). In both cases it creates new e-mail with current file attached.