By default, email tracking for both opens and click-throughs is enabled for all outgoing emails. This feature provides valuable insights by recording the exact timestamp when a recipient opens your email or clicks on any embedded links.
There is an option to disable tracking before sending an email. When you are composing an email below the subject line will be a checkbox to disable or enable tracking.
You may want disable tracking as some email providers such as Outlook, block unknown sender's images by default. The recipient will be notified that images have been blocked and it may be suspicious. If your emails are consistently being blocked, you might consider this option.