Emails go to spam when your email service provider identifies them as suspicious and tries to keep them away from your inbox. It can be because other recipients have flagged the same email as spam, or the email subject line or body text contains spam-trigger keywords like “free,” “easy money,” or “no cost.”
Having said that, not all emails that go to your spam folder are actually malicious. Most of the time, it’s more of a precaution and shouldn’t be a concern.