The word "due" can be an adjective, noun or adverb. It has many uses but the most commonly uses are as follows: adjective 1. owed at present; having reached the date for payment; owed in the future: - This bill is due now. (required to be paid) - This bill is due next month. 2. describing something that is appropriate, fair or expected: - When you climb a monutain you must take due care (the amount of care and safety that is necessary in such a dangerous activity) - You should pay back the money that you borrowed from me in due time. (pay back when you said you would or at least in a reasonable and fair amount of time). - Companies in Canada must use due diligence to protect the workers from the hazards associated with their work. ("due diligence" means the amount of attention and effort the company should make to reduce the danger to an acceptable, safe level. "Due Diligence" is a legal defence used in court to show that a company or a person did everything that was reasonable in the circumstances to protect the worker. 3. when something is scheduled to happen, expected to be ready, expected to be present or arrive: - The plane is due at noon. - Dinner is due to be served at 6 PM. - I am due to get lucky very soon (DP - let it go) noun 1. a regular fee or charge payable at specific intervals, especially to a group or organization: - I must pay my gym membership dues (fee) every month. - Every year I pay $150 in dues (fees) to the Canadian Board of Registered Safety Professionals.

"When is it due?" = When will something arrive/be complete? So if you tell someone "I'm sending you a package via post," they may ask, "When is it due?"

Thank you, dreyfus

the use of the word "via" e.g:i sent a message via internet. the use of "due" e.g: my flight was cancelled due to the bad weather.

the use of the word "via" e.g:i sent a message via internet. the use of "due" e.g: my flight was cancelled due to the bad weather.