Ever since I abandoned Outlook 2016 back in August for Thundrerbird, the amount of spam EMails I get is just about zero! I have not tweaked any of the default spam settings in Thunderbird, nor have I done anything with my ISP's (Xfinity) settings (not even sure I can). Using Apple Mail’s Junk Mail filter. To find the Junk Mail filter you’ll need to open up Mail then go to the menu bar at the top of the screen click Mail then select Preferences from the drop.
If junk mail isn’t highlighted in brown to indicate it’s junk, check your junk mail preferences. • Choose Mail > Preferences, then click Junk Mail. 
Make sure “Enable junk mail filtering” and “Mark as junk mail, but leave it in my Inbox” are selected. • If you chose the junk mail preference to exempt addresses in the Previous Recipients list from filtering, check that the list contains only valid addresses you want to receive messages from. • If the problem persists, click Reset in Junk Mail preferences to reset the junk mail database to its original information. Resetting the database removes everything Mail has learned from you about what is junk or not junk, so you need to help Mail identify junk mail again. Be sure to tell Mail when it misses junk mail: Select the message, then click the Junk button in the Mail toolbar (or use the ).
Preventing unwanted messages from showing up in your inbox can be integral to enjoying email. In this article we will walk you through the process of creating mail rules that will direct messages to other folders or the trash based on conditions you specify. We will also discuss how to update rules to include additional senders or other criteria, and provide some common-sense guidance about effectively using mail rules in general. Mail rules allow you to direct messages out of your inbox into another folder or trash automatically, based on their sender or other conditions.
Rules can be set up on iCloud.com if the email address is the one you use for iCloud (it can end in either @icloud.com, @me.com, or @mac.com). For your other email addresses, rules can be set up in the Mail app on a Mac. If you set up rules using they are very effective, immediately directing messages to the specified folders on all your devices.
If you set up rules using the Mail app, they are effective only after you start up your Mac and open the Mail app. At the end of this article, I will make some practical suggestions about how to address that, and other aspects of using mail rules. There may be a few different types of undesirable mail. I suggest that a folder (and rule) be set up for each of the types. Below are examples of different different types of messages you might set up folders for: • Vendors – Messages from businesses you enjoy visiting such as restaurants, supermarkets, clothing stores or tech vendor websites. You might want to look at these later for special offers and coupons. • Spam – Messages from business you don’t prefer, including anything offensive or sketchy.