The difference between direct and indirect supervisor is the presence of the supervisor. Direct supervision means a supervisor is psychically present.
When mailing a certified letter, a person should expect it to take from three to five days to reach its destination. Depending on how long it takes the recipient to pick up the letter, the process can take up to 21 days. People who send certified mail receive a notification to prove that the letter has been received by its recipient.
The United States Postal Services reports that as of January 2011, it takes an average of one to three days for First-Class Mail to arrive at its destination. Priority Mail takes an average of one to two days to arrive, according to the USPS. USPS only includes the time a package stays in transit in their estimations.