Settings > Personalization > Lock Screen. Turn off the option for "Get fun facts, tips, and more from Windows and Cortana on your lock screen"

EDIT: If you don't have that option, set your background for Slideshow or Picture, as the default Windows Spotlight setting will force you to see their stupid little tips and other bullshit. It's worth setting it to Picture or Slideshow anyway, as it's one more bit of telemetry that MS won't be getting from you.

It's one of the things we always turn off when prepping new/replacement computers for our employees where I work.

Settings > Personalization > Lock Screen. Turn off the option for "Get fun facts, tips, and more from Windows and Cortana on your lock screen"

It's one of the things we always turn off when prepping new/replacement computers for our employees where I work.