To select the shipping method while generating a sales receipt, follow the below instructions

1. Click on Sales Receipt
2. Click on the '+' icon and generate a new sales receipt
3. Take the cursor to shipping method and scroll down to the available options
4. You will be able to see the following options to select the right shipping method for the particular sales receipt. 

(Standard Ground, Priority Shipping, International Shipping, PO Box Delivery, and Freight Shipping)

5. Select the shipping method and add other details to generate a sales receipt successfully 
6. And, click on save