First and foremost: Canvas does not have an email feature, but through “Notifications” process, Canvas can forward notices to the email you have set for this. And, yes, sometimes those notifications are moved to your spam or junk mail folder on whatever email system you are using.
The trick is to edit the setting on your email to recognize that email sent from Canvas are not spam. Unfortunately this is different on all email systems. Here is some help for the big two:
(From Canvas Community Posting 1-31-2019)