Customize the Lock and Sign-In Screens

The Windows 11 Lock screen appears when you wake up, power on, or lock your PC.

When you tap a key, click the mouse, or touch the display, the Sign-in screen appears so you can sign-in and get to work.

Tip: When configured, features like Presence Sensing and Windows Hello facial recognition work together to sign you in immediately, bypassing the Lock and Sign-in screens.
Defaults
The Lock screen is configured with the following defaults:

The background is provided by Windows spotlight, which displays a new, high-quality photo from Bing every day. These photos are pleasant and of very high quality, and they are accompanied by interactive and informational bubbles that provide you with more details about that day's photo.
A large, centered time and date display.
A Network status icon and, for laptops, a battery life status icon with percentage in the bottom right of the display.
With a new install, you will see a single widget, centered on the bottom of the screen, for Weather that displays the weather forecast using the current location and temperature unit. But it is more likely that your Lock screen displays four widgets aligned horizontally, which is the maximum Windows 11 allows.
If an app is playing media and your PC's screen is locked, you will also see basic media playback controls below the Weather widget or whatever widgets you've configured to appear on the Lock screen.

The Sign-in screen is configured with these defaults:

The background is the same as that used by the Lock screen, so it uses Windows spotlight by default as well.
The profile picture and username for the most recently signed-in user appears center on-screen with PIN, password, and other sign-in options.
If there are multiple users configured on this PC, you will see icons for them in the lower left of the screen.

Customize the Lock and Sign-in screens
You can customize the Lock screen and Sign-in screen if desired.
Customize the Lock screen
The Lock screen is surprisingly customizable, though the options fall into two main categories: The background it displays and the widgets it can contain. Each can be configured in the Settings app by navigating to Personalization > Lock screen.

Configure the Lock screen background
The "Personalize your lock screen" option lets you configure the type of background the Lock screen displays.

There are three choices.

Windows spotlight. As noted above, this is a different high-quality image each day with accompanying details about the image.

Picture. This lets you choose an image using a grid of recent images or click "Browse photos" to find a specific image.

Slideshow. This presents a more complicated set of options with two "albums" (the contents of your Pictures folder and the Public Pictures folder) preselected as the sources for the slideshow, a lame "Get fun facts, tips, tricks, and more on your lock screen" option you can toggle on or off, and a...