@Pedro_Santos
Welcome to the expat.com forum and good luck with your new life in Bulgaria!
I think it's very common for village houses not to have a proper address. Our house doesn't have an official address. But whether or not you have one, it doesn't really matter.
Very little comes by regular post. And at my house I've never received any mail directly. The local post office normally holds it there, and calls me to tell me they have something for me.
Most deliveries in Bulgaria come by courier. Most commonly Econt or Speedy, but some companies have their own courier/drivers. In this case, they will normally email and/or message you (SMS or Viber) to alert you of a delivery, and usually the driver will call too, just before arriving.
Normally, they don't arrive directly at your house (unless you have an official address AND it shows up on Google Maps or equivalent). I meet them at the fountain at the entry to our village. And if it's small I grab the item, and if it's large, I get them to follow me back to the house.
I use Emag a lot for general stuff (most vendors deliver with Econt/Speedy). For furniture, I've had deliveries by Jysk and IKEA. DIY, tools and building materials from Praktiker. Appliances/TVs from Technopolis. Medicines and supplements from Sopharma. All have good websites and it's easy to create your own account. Some will do COD, but mostly I pay by debit card, or make a bank transfer after placing the order.
I used to use Ebay (UK) and Amazon (UK) a lot, but post-Brexit it's usually a hassle. But I now order from Amazon (Spain) instead as that's EU, and no problems. Most Amazon orders are sent by international courier rather than regular mail. Emag is not as good as Amazon, but it's very convenient as it's the local option, so I will try Emag first.
After a couple of deliveries, your local post office, Econt and Speedy offices will have your name/mobile number in their system. And some drivers are pretty regular, so they might remember where your house is.
I get almost everything delivered instead of going to the store.
The only aggravation is food, I think you'll find you still need to find your way down to the local supermarket or produce market. But most villages have a bit of a bus service, and taxis might be possible too. Our village is in the Balkan Mountains (beautiful area) but only 10km to Kazanlak, which is a good-sized town with Lidl/Kaufland/Billa and a great bazaar. The bus runs 3 or 4 times per day, for 1 leva. Most taxis charge me 10 leva to get back to the house. It's also reasonable to go by bicycle, but these days I find my electric one more enjoyable! (Ali Express order, but from an EU warehouse. And electric mountain bikes are awesome, every village house should have one!)
The language can be an issue, as I don't speak Bulgarian. Most Econt/Speedy drivers have a bit of English these days. If not, I have the minimal Bulgarian for: Econt? Speedy? Fountain? 5 minutes? 10 minutes? 15 minutes? The SMS/Viber/email messages are easy to translate on your phone these days, so it shouldn't be a surprise when a driver calls you a couple of hours later.