How to change the defult focal length to 150mm?

hello everyone.i am new blender user.
every time i open blender,i like to change the focal length from 50mm to 150mm.is there any way to change this defult 50mm to 150mm by start?thanks a lot!
length

Hi and welcome,

File > Defaults > Save Startup File

More explanations:
Startup Scene

oh man,that so easy haha,perfect!
thank you!