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.
Certified mail is a USPS service that allows you to confirm delivery. The Postal Service keeps certified mail proof of delivery records for two years. When you send certified mail, you get a receipt that can be useful if you are mailing a legal, financial or other document that must meet a deadline.