BulkSignature has functionality that automatically updates and syncs email signatures every 24 hours. However, there are some conditions that you should be aware of to ensure the function works properly.
Even though the tool implies automatic email signature installation, you may encounter possible delays.
BulkSignature applies email signature through the Outlook settings using Outlook API. Thus, the email signature installation requires a page refresh or session update (login/logout) to make the change visible.
Even though the email signature update is performed, to see the changes you need to refresh your browser. When you refresh the page, the whole Outlook interface also gets reloaded, which allows you to see the changes that were made.
To put it short, to see the updated email signatures your users simply need to reload their Outlook pages.