Grub
Grub
You have two storage devices: a 1 TB hard drive running Pop-OS and a 128 GB SSD with Windows. Linux boots first because it uses UEFI, while Windows boots via legacy. I found information about GRUB that lets you choose boot options at startup. Let me know how to configure it for you. Thanks!
The operating system you're running is a Linux distribution. Most prefer Grub as their standard bootloader. If your system doesn't use Grub, changing it might not be straightforward, though you could potentially set up your chosen distribution to support Windows booting.
PopOS relies on systemd-boot, but it only scans for Windows on the same partition, so it may not locate it automatically. You might need to use a different approach: https://unix.stackexchange.com/a/628581. Alternatively, adjust the boot drive priority in your BIOS settings.
It's easier to use Grub without installing it from the beginning, since you wouldn't have needed to set it up yourself.