Acquire Liquidity Provider (LP) tokens and a share in the fees by contributing your tokens to a Liquidity Pool.

Liquidity Provider Tokens

For instance, if you contribute ONUS and HERA tokens into a Liquidity Pool, you will earn HERA-ONUS LP tokens.
The quantity of LP tokens you earn is based on your share of the HERA-ONUS Liquidity Pool.
You may also withdraw your liquidity to redeem your assets at any point in time.

Trading fees are paid to Liquidity Providers

Liquidity Providers get a share of the trading fees when individuals use their liquidity pool.
Every time a trader uses Heraswap, he's charged 0.25%, of which 0.05% goes into the Liquidity Pool of the traded swap pair.
You can also bring your LP tokens to Yield Farms while still earning your 0.05% from trading fees, making being a liquidity provider extra appealing.

Impermanent Loss

Providing liquidity is not risk-free. You may suffer an impermanent loss, which is why it's important to DYOR*.
*Do Your Own Research