Emails end up in the junk mailbox.
What can be done?
Hey there. There’s a lot of factors that go into email delivery. Are you referring to email marketing through Wix or email in general?
E-mail in general yes. Any tips? Some experts says it has to do with some config at wix.
Wix shouldn’t impact your own private email’s delivery - that’s all configured through your email provider 
Not my private email, but email accounts under a domain / website here at wix.
often when emails are sent, they end up in the junkmail when they arrive.
Since Wix is a reseller of G Suite - all mailbox come preset with G Suite settings, including your domain verification. I would connect with support to see if there are any additional DNS records you can add - but email delivery can never be guaranteed, especially since the receiving inbox has its own set of filters as well.
Go to gmail and research how to add Mx records to verify the email account.