Yes. I often purchase PSN digital codes directly from Amazon.com, which are emailed to me (no physical card involved). https://www.amazon.com/20-PlayStation-Store-Gift-Card/dp/B004RMK4BC/
You add them to your PSN wallet, per the guide instructions. https://www.playstation.com/en-ae/get-help/help-library/store---transactions/voucher-redemption/how-to-redeem-a-voucher-code-using-playstation-app-or-web-browse/
When you have a sufficient balance in your PSN wallet, you can purchase PS+. https://www.playstation.com/en-gb/get-help/help-library/playstation-plus/information---benefits/how-to-buy-playstation-plus-membership/
Alternatively, you could order a PS+ digital code directly and redeem it straight to your account without going through your PSN wallet. https://www.amazon.com/1-Year-PlayStation-Plus-Membership-Digital/dp/B004RMK5QG/
So you seem pretty new to all of this:
You'll get a 7 or 14 trail period through PS+ (dependent on the offer that they're running at the time) - This is technically free but one of those that will auto-renew at the end if you don't cancel.
If it auto-renews its about £6-£7 per month, however if you buy 12 months up front it's about half the price. Currently $39.99 on Amazon atm if in the US https://www.amazon.com/PlayStation-Plus-Month-Membership-Digital/dp/B004RMK5QG
It's also available on Amazon for the same price:
I added an additional year to my subscription, which is now good till 2021, and I'm wondering if I should push it to 2022. People need to jump on this because PS Plus going for this price doesn't happen often, unlike XBL deals, which are way more frequent.
Price matched on Amazon as of this posting.
Yup - on the amazon us site, you don't even need to wait for the card to be shipped to you. They'll just email you a digital code that you can enter on your PlayStation. The same goes for PSN cash - you can just buy it all through amazon and never have to give sony any credit information.
http://www.amazon.com/Playstation-Plus-month-Subscription-Download/dp/B004RMK5QG
Sorry do you mean like the seller is amazon because im trying to buy This and im not sure if its sold by amazon