[Sudhir]

Hi HARSHITA, it cannot be done through Workflows. But yes both Process Builder and Visual Workflow will work.

In interview, you are generally given less information to check what other queries the candidate will ask in order to take a solution.

[Sudhir]

Make use of UserInfo and/or Timezone class.

https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_methods_system_userinfo.htm

and

https://developer.salesforce.com/docs/atlas.en-us.apexcode.meta/apexcode/apex_methods_system_timezone.htm

[Sudhir]

You can use either Process Builder or Visualflow wherein you can call an apex to do insert or update of unrelated objects.

Refer this link to validate your decision: https://developer.salesforce.com/docs/atlas.en-us.salesforce_vpm_guide.meta/salesforce_vpm_guide/process_which_tool.htm