Support for the Office 2013 versions of Office 365 has ended and are no longer being offered for download in the download sections of Office 365 Home and Office 365 for Business.
If you still have it installed, you will receive Security Updates until April 10, 2018.
Upgrading to Office 2016 is highly recommended and also already part of your Office 365 subscription. However, common reasons why you might still need Office/Outlook 2013 are;
When you still need to (re-)install Office 2013 as part of Office 365 for whatever reason, you can still download it by using a direct link or by using the Office 2013 Deployment Tool.
Continue reading: Downloading Outlook 2013 from Office 365 after March 1, 2017