To choose the date format to be used when naming the output file follow the steps below
Step 1. Go to Outlook > Email to PDF toolbar > Output Settings button > File Naming tab > Date Format to use on output file.
Step 2. You will have 3 parts of naming the File as shown in the screenshot below.
From the drop down fields select date format field in the 1st part or 2nd part or 3rd part of the file name (e.g. ReceivedTime, CreationTime, LastModified Time, SentOn etc.) and save.
Each of the date formats are substituted by the value of the date/time components.
Step 3. Select an Outlook email to process, for example, if the chosen file naming is “Subject _ ReceivedTime” (under Output Settings > File naming tab) and the date format is ‘yyyyMMdd_HHmmss’, when you save the email to PDF, the save dialog box should show ‘Subject_yyyyMMdd_HHmmss.pdf’ file name format.