If your email address uses a unique domain name associated with your own business or website (ex: JaneDoe@JaneDoesBusiness.com instead of JaneDoe@gmail.com), you might notice that your emails often get sent to your recipients' spam or junk mail folders. This can make it very inefficient to communicate effectively with other businesses, and can also affect your own customer outreach. Because your emails likely come from a custom domain hosted by a hosting provider (such as GoDaddy.com or Register.com), to prevent your emails going to SPAM, you would need to follow similar guidelines that many businesses use to prevents emails from going into customer's spam folders.
We would encourage you to reach out to your hosting provider for information on how to set up SPF & DKIM on your domain. Businesses use use SPF (Sender Policy Framework) and DKIM (Domainkeys Identified Mail) records in DNS which helps to authenticate email messages. Google and other email providers use email protection standards to verify that messages are authentic, and until the messages sent from the domain are authenticated using those steps, the chances that email providers will continue to recognize them as spam are significantly higher. In addition to reaching out to your website host for help, you may also find the support you need by browsing their help articles, or inquiring with your own IT person if you have one for next steps.