A fiat-on ramp is a way to get cryptocurrency from fiat, or regular money.
On-ramp refers to an exchange or another type of service where you have the ability to offer fiat money in exchange for cryptocurrency.
An on-ramp essentially allows you to convert fiat money into cryptocurrencies. These platforms are typically known as exchanges, where they base the amount for the fiat-crypto transaction on the current market rates.
In fact, there are three ways through which you can get cryptocurrencies as well as other blockchain assets.
First, you can mine them, and this means that you can offer your computing power to a blockchain network in return for coins or tokens. Another way is to sell goods as well as services and accept cryptocurrencies as a way of compensation for your efforts or products.
However, these options might not be available for just about anyone, and this is where the third way, the fiat on-ramp, will allow you to buy cryptocurrency by simply using cash. All you have to do is visit an online exchange or physical crypto ATM, and take your fiat currency and exchange it for an equivalent amount of cryptocurrency.
The main reason they are called on-ramps is due to the fact that they provide you with access to the entirety of the cryptocurrency ecosystem.
Then you have cryptocurrency off-ramps, which are the opposite of on-ramps. They allow you to convert your cryptocurrency into fiat currency, although you can also get products or services.
In the previous on-ramp scenario, you were a user that needed to get into the cryptocurrency ecosystem, but what if you wanted to get out of it? This is where off-ramps come into the picture. You can trade back into fiat through them, due to the fact that fiat currencies, in a lot of parts of the world, are still the primary means of conducting purchases or payments and so on.