How to add keyboard shortcut for "Move to Predicted Mailbox" in Apple Mail?
There are built in shortcuts for the Favorites bar – the bar shown here that has &quot;Mailboxes Inbox (5) 2021Q1 2020Q4 (1)&quot;.

The shortcuts are ⌘+Control+&lt;number&gt;, where number is the position on the bar with &quot;inbox&quot; getting position 1. So to move to 2021Q1 on my favorites bar, I hit ⌘+Control+2 (probably my most hit keyboard shortcut since my current archive folder also holds this spot on my favorites bar).
If you don't see the favorites bar, show it from the View menu, &quot;Show Favorites Bar.&quot; Then drag your preferred folders from the folder list on the left onto the favorites bar.