I still need to shop in-store due my work hours not allowing me to be home when items are delivered by my mail carrier, but I want to be environmentally friendly and not have paper receipts if offered digitally. I use Walmart Pay and Sam's Club's Scan and Go for shopping in-store and receive digital receipts for them. I don't understand why online receipts aren't accepted in this digital age... I still have to scan the product barcode that I own that matches the receipt I also have. This is really frustrating since so many of my receipts are emailed to me for my in-store AND online purchases.
I use Walmart Pay all the time. But I wanted a receipt. @Dana was kind to let me know that I could pay a penny as cash and then switch to Walmart Pay. This will generate a receipt. Please note that some of the new Walmart registers do not let you do this.
If you are at self checkout, you will have to touch the penny to put it in and then touch the screen to change the payment method, but other than that, it is touch-less.
As for your other grocery stores, check on their site. Some of them may allow you to get a receipt. Publix, for example, lets you get your receipt emailed AND get a paper receipt, but you have to enter your phone number. Walgreens allows a digital receipt OR a paper receipt, though I have been told they will give you a paper receipt if you need one. Again, you have to enter your phone number at Walgreens.
Home Depot has had the ability to email a receipt and/or print a receipt for years.