Question about sending extension through courier?

[ColorMePanda]

Well I was thinking of sending my extension request through a courier service but I am not very familiar with their services.

How reliable are they? What one would you recommend using?

And on the extension it says in the guide that when you mail it, not to mail it in a prepaid envelope so then how would I go about sending it?
Could I just put it in a regular envelope and still have it sent through courier?

Alot of questions I know but just curious.
Thank you so much if you can help.

Also, what is the most affordable one?

 

[Suin]

are you in Canada? there are a few quire reliable courier services in Canada - Purolator is one of them and they are not expensive to ship withing Canada.
they don't ask to send in the prepaid envelope because they may have their own service to send you reply back - they just don't want to deal with couriers themselves.
just go to the courier and mail it from them - it will be just one way, no return.
good luck!