To mint Hop tokens you need to lock your asset in the Hop Bridge contract on Ethereum mainnet. Hop will then mint the equivalent amount of Hop tokens on the destination chain of your choice. For example, if you lock USDC you receive hUSDC.
To do it, head to the “Convert” section in the navigation bar and select the option “via Hop Bridge”. Then transfer your assets from Ethereum mainnet to the destination network (e.g Polygon) by clicking on “Send”. After 10-15 minutes you should receive your Hop tokens in your wallet on the destination network of your choice.