Please be more specific.
Is it on BIOS or UEFI?
Did you press F2/F8/F12 during the computer boot?
Did you burn the Kali ISO file on a USB flash or DVD?
What burning software did you use to burn the ISO file? Or did you just copy and paste the Kali ISO file into USB flash dan didn't use any burning tool?
What is the brand and model of your laptop?
Sorry, but we have to ask.