Even though kali Linux (OS) is installed on your device, it’s likely that Windows will not detect and thus it won’t boot automatically. For this reason, you will need to enter the BIOS setup and set the default boot order to boot from Kali Linux.
Here’s how to do that:
First, enter the boot setup- Turning off the laptop/computer, and pressing the ESC key repeatedly. Different laptops have different keys to enter the Boot Setup Menu. (For HP press F10), (Lenovo and Dell F12)
Enter the system configuration tab, and use the arrow keys to select this tab. Here you will see the boot option. Select it.
If Kali Linux has been installed on your computer. Then you should see two boot options. Windows and Kali Linux. Select Kali Linux from there and save and exit settings.
After changing the Boot OS, restart your device now and it should boot the OS (Kali Linux) instead of Windows OS. And yes, you can repeat the process if you want to boot from Windows OS directly.