How can I display inside each story Total Time spent by Each User ?

Cosmin V

If for example 3 users have worked on a story, I want a list with 3 people and the sum of their time spent.

I don't want this in a report, I want it inside the story. It could be a calculated custom field or something.

I can even hardcode 5 users that I care about.

Tarun Sapra

You can use a scripted field from the script runner plugin 

https://scriptrunner.adaptavist.com/4.3.1/jira/scripted-fields.html and calculate the time-spent on the stories

some code example here (in 2nd answer) - 

https://answers.atlassian.com/questions/37533660