If you are a business and use your own domain, there are steps you can take to stop your emails going to users SPAM or Junk forders. Especially if those users have a @yahoo or @gmail address, see this article

Does your business send email to Gmail or Yahoo accounts?

Does your business send email to Gmail or Yahoo accounts?

If you do not have your own domain, then the fault could be the recipents accounts themselves. Ask them to check your address is not in their “blocked” email list.

The trick is to configure a number of key DNS settings so that your recipients mail server is confident that the incoming mail comes from a legitimate source. Legitimate emails should not end in your recipients Junk/Spam folder.