ITS allows you to deploy Interchain Tokens. An Interchain Token is an ERC20 that is connected to ITS upon deployment. It comes built in with the interchainTransfer() function, which allows users to bridge their token between any blockchain which it is deployed to. To deploy this token you can go through the Interchain Token Factory contract. When you trigger the registerCanonicalInterchainToken() function that will trigger the flow of registering your custom token with a Lock/Unlock token manager type to your token's home chain. Now that you have registered your token on the home chain you can call the deployRemoteCanonicalInterchainToken(). This will deploy an Interchain Token on a different blockchain that will be connected to your canonical token on the home chain you registered when you called the previous function. Note: This is just one of many different flows you can choose to follow when interacting with ITS.
Once your token is connected to ITS you can call the interchaintTransfer() function to send a cross chain transaction for your token. If your token inherits in the Interchain Token Standard then you will have this function built into the token. The interchainTransfer() will trigger a flow that will interact with ITS to either lock or burn your token on the source chain (depending on the Token Manager type) and then mint your token on the destination chain.