A stablecoin on-ramp is a service that accepts national currency from a bank transfer, card or payment app and delivers stablecoins to the customer's wallet. It is the entry direction of the bridge between bank money and digital assets, and both directions are compared in Fiat On-Ramp / Fiat Off-Ramp.
An on-ramp can source the coins in two ways: buy them from its own inventory or a market, or, if it is an approved customer of the issuer, pay money in and have new coins created through minting. On-ramp providers must run identity checks on customers and screen card payments for fraud, which is why the step is often slower than the transfer that follows. The same idea from the asset side is covered in crypto on-ramp, and the reverse service is the stablecoin off-ramp.