For example if you have a contact form that keeps going to the spam / bulk folder here is how to add a filter to send it to your inbox:

1. Login to your workspace email account 

2. Click on "Settings" and then "Spam Settings"

3. Click on "Custom Filters" and then "Add New"

4. Change the "If" drop down to "Subject"

5. Change the add this "Contact Form" to the "Contains" field

6. Set the "Then move to" to "Inbox"

7. Click okay. Your new filter should show up now. And all emails with "Contact Form" in the subject should be sent to your inbox.