Selling help

Been a lil bit. Hope everyones turkey day was enjoyable. Update on getting ready to sell stuff. I finally got a checking account set up for my sell link to paypal account and partly set up paypal. Still waiting on debit card to arrive. But questions on shipping. I plan on getting those preset priced us post office boxes, that will make easier to quote shipping price. If I start selling bigger item I'll ask for advice them. I just plan on starting with small items. Gain all your trust. Question is when I sell do I just write my own address label and ship. Or do most of you prefer what? Thanks for your patience with me life sure can be busy.
That's how I do it. I make a separate address label and tape it to the box. I cover the label completely with clear tape in case it gets wet it's still legible.