If for some reasons supervisor has to create leave requests for employee he/she can doing it by staring the usual New Absence form. But when supervisor accesses it there is one more extra field For Employee. There supervisor can chose employee he is creating requests for. The rest of the process in the same.
New absence booking form
Holidays created by supervisors are auto approved if those flags are selected in Setting - Advance Settings..
Screenshot of advance setting page at TimeOff.Management