Creating worklogs for yourself requires the Work On Issues permission. Creating worklogs for other team members requires the Log Work for Others permission.
You can log time on Jira issues in any timesheet.
When you log time for another team member in My Work, the Calendar view is not available.
is disabled, but if enabled, any Tempo Timesheets user can set start and stop time when logging time. This means that the Date field in the Log Time dialog box changes to a date/time field in the enabled case. The current time is used as default.
A useful reading on the difference between my JIRA worklog and my Tempo worklog.