who decides user stories code example

Example: who writes user stories

it is done by PO.

As a tester I only write technical user stories
which whenever I need to search for a new tool
or if I need to setUp a new platform.

User story is a tool used for to capture a 
description of software feature from
and end-users perspective. Basically user story
describes the user and their needs like what they
want and why they want it. I can say user story
helps to create sipmlified description of requirement.
***
As a tester I only write technical user stories
which whenever I need to search for a new tool
or if I need to setUp a new platform.


**example user story
as a tester I like to be able to use new 
testing framework so that my testing process
would speed up