When you insert a file into an email message in Outlook, the Insert File window appears where you can browse to and select the specific file you want to attach. The files that appear within a folder are typically not sorted in any particular fashion. If a folder contains many files, finding the one you want to attach may become frustrating.
Fortunately, you can arrange the list of files from right within the Insert File window. Arranging the files by name puts them in alphabetical order which might make it easier to find the one you’re looking for. To sort the files, right click on a blank area in the Insert file window, choose Arrange Icons By and select Name.