Hi there, Inayat! This is Marc. Thanks for reaching out to the community.
This is usually caused by the Fn lock setting being toggled, which makes the special icons (volume, brightness, etc.) the default instead of the standard F1–F12 functions. To switch it back, try pressing Fn + Esc (on most laptops) or Fn + Lock (sometimes shown as a padlock symbol) this turns off the Fn lock. If that doesn’t work, check your BIOS/UEFI settings for an option like Action Keys Mode or Function Key Behavior and set it to “Function Key First.” Some manufacturers also let you adjust this in their keyboard utility software (like Dell Quickset, HP Command Center, or Lenovo Vantage).
Let me know if this helps or if you need further assistance.
Best regards,