According to Sarah, recorded delivery

W: Lee, where are you going?
M: To the post office, Sarah. I am going to send some packets to Mary. Do you know the best way to send them?
W: Well, if your need is for a record of posting and delivery rather than compensation for loss, recorded delivery is particularly suitable for sending documents and papers of little or no monetary value.
M: Well, what can we send for recorded delivery?
W: All kinds of inland postal packets except parcels, airway and railway letters and parcels. The service does not apply to mail for the Irish Republic.
M: I see. How do I post them?
W: You should get a certificate of posting from the container in the post office and follow the instructions shown on the reverse. The certificate will be your record of posting.
M: Can I send anything in the post?
W: No, you can’t. You must not send bank notes, currency notes, and some valuable things because there is no special handling in the post. Recorded delivery mail is carried with the ordinary unregistered post. And there is no special security treatment.
M: How do we use recorded delivery?
W: Well, when your letter or packet is delivered it is signed for by the recipient and a record is kept by the post office. The post office does not undertake to deliver recorded delivery or any other mail, to the addressee in person, but to the address shown. You can obtain confirmation of delivery by completing an Advice of Delivery Form either at the time of posting or later. This form will be signed by a post office official, not by the addressee of the recipient. A fee is payable, which is lower if the form is handed in at the time of posting.
M: Is there any compensation for loss?
W: Well, compensation is limited. Compensation may be paid for loss or damage, but will not be paid for money or any other inadmissible item. If you want a speedy service for articles of value with extra security of handling en route, and wish to have compensation in the event of loss or damage you should use registered post.
M: What can we send if we use registered post?
W: Any first-class letter or packet except airway letter or railway letter.
M: How do we post? I mean what should we do?
W: Well, you should make sure that the packet is made up in a strong cover and then, it is fastened with wax, gum or other adhesive substance. Hand the packet to the post office counter clerk together with the cost of postage and the registration fee. Do not post it in the posting box. Make sure that the fee paid is adequate to cover the value of the contents. The counter clerk will give you a certificate of posting which he has initiated with the date stamped.
M: Is there any special security for the registered post?
W: Yes. All registered mail receives special security treatment. Packing is very important because registration is not in itself a safeguard against damage. The contents of registered packets must be adequately packed.
M: How do we pack them? Do we have to use special envelopes?
W: Yes, you have to send the articles in one of the registered letter envelopes sold by the post office. These envelopes are already stamped for first-class postage and have the minimum registration fee.
M: What about the compensation?
W: Compensation will not be paid for the following articles, such as bank notes, currency notes, trading stamps, coupons and some valuable things unless they are enclosed in one of the registered letter envelopes sold by the post office.
M: I see. How does it deliver?
W: The recipient on delivery signs for your registered mail. The post office does not undertake to deliver registered or any other mail to the addressee in person, but to the address shown. You can obtain confirmation of delivery by paying an additional fee, and completing an Advice of Delivery Form either at the time of posting or later. If you require the recipient’s signature on the Advice of Delivery, the form must be handed in at the time of posting otherwise a post office official will sign the certificate. The advice of delivery fee is lower if the form is handed in at the time of posting.
M: Thank you very much for all this useful information.