How do you ask for additional postage on eBay after the buyer had paid?

[JasonMomoasgirlfriend]

The buyer emailed me asking if I can send the item by first class rather than 2nd because they want it sooner. But I can't see how to add on additional postage.
Google tells me I should go to "sold" then "send invoice" but I cannot see that option

Well, she has messaged to say the item has arrived and is perfect for the person she is giving it to and that she will send the money right now....so an just waiting on an email from PayPal to tell me I have been sent money.
Fingers crossed

Aw she sent £3.

So there you go, not everyone is a scammer after all. 🥰 Hurray :)

Good to see a "happy ending" OP!

Yes I'm glad and I feel bad for doubting her now!