Clock speed i7-8750H

[Hepi]

Hi guys,
on the frequency clock speed of intel i7-8750H is 2.2Ghz and up to 3.9Ghz or 4.2Ghz, how and where to set in the laptop for getting up to that 4.2Ghz ? Is it set automatically by the system in each running program or need to set it up manually ?

Would you please help to advice me?

[David (PassMark)]

It should hit the maximum clock speed (automatically) when running 1 thread of CPU intensive load. Unless thermally limited, or limited in BIOS.