If you have created at least one time entry for yesterday, you will see an option to duplicate time entries from the previous day:
There are a couple of rules as to when this option will be shown:
the option to duplicate time from yesterday will only show for today
the button is only visible in Day view
only if there is at least one time entry logged the day before will you have the option to duplicate that time
weekends and holidays are not taken into account
if you have Autotracking turned on, the option to duplicate time will not be shown
autotracked time entries will be ignored. In other words, they will not be copied
recurring budgets - if there is a subsequent recurring budget for the day you duplicate the entry, the entry will be created for the corresponding budget
if there is no valid active budget for today, the option will not appear. In other words, entries that do not have a valid budget for today will not be duplicated