Run a duration field when incident is created and comlete when closed

[sunil kumar6]

we want to create a duration field which runs from 6am to 6pm monday to friday once incident is created and completes when incident is resolved

[viNikier]

You can use the Metric  for that, to measure how long this incident was open.
https://docs.servicenow.com/bundle/xanadu-platform-administration/page/use/reporting/concept/c_Metri...

But if you need to put that on a field you can create a Business Rule, and use the created and resolved to calculate the duration.