Ebay are moving to Simple Delivery.
From 15th that will be the only method of posting, unless items are below £10 and lighter than 100g.
A lot of your listings now show Simple Delivery at £2.70.
The buyer pays that amount but it goes directly to Ebay and Ebay send you a label to post or a QR code to use when you drop off the item.
The issue for you is, apart from waiting for payment, that you will not receive any payment for the postage from your buyer so potentially, on your low cost items, it will be costing you to sell an item.
This is hard for older sellers (I am 68) and the choices are stark: adapt or leave Ebay.
On a very basic level you need either a smartphone or a printer.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)