Chiedo come si stabilisce il prezzo di vendita delle foto e come si stabilisce il pagamento?
The price to the user is set by Adobe based on the Plan that the Buyer has selected. You do not have any input as to pricing of your images. Detail on how to request a payment is shown here:
You don't. This is not eBay where you set prices and transact directly with customers. Adobe Stock handles pricing and payments for you the same as most other royalty-free image houses.
Please read the Stock Contributor User Guide about Payment & Taxes.
Post back if you have more questions.