type in a random mess of capital letters SOMe PEOPle lIkE tO TYpE iN A LoGiCAL MAnNER, WITh CapITals aT tHe bEGiNnIng Of ThE SENtENCE and smaLl LETTErS EVeRYWHErE eLsE. NOT Us. NOt Us. Your joB iS to tAkE A SenTEncE Of A
LL SMAlL LeTTeRS, And rANDOmly ChAnGe sOMe to caPiTAl. ThiS iS a Code gOLF so tHE SmaLleST coDE WIll win.  

the input will always be small letters and spaces with punctuation only.

random meaning running the code multiple times will always yield different results. 

test cases for this will be hard since it involves random elements. 

here is a shitty example with python

https://onlinegdb.com/Hy0_gEEKH
Python 3, 59 bytes



i=input()
while i:print(end={i,i.upper()}.pop()[0]);i=i[1:]


Try it online!

-4 bytes thanks to Chas Brown

Uses set.pop() to randomize.