omni address is only a bitcoin address. you can send tokens to any bitcoin address, and they will just sit there until you want to send them out. to send them out, you need to import that bitcoin address' private key into an omni wallet. (notice all: if you dont know how to store the private key safely, dont use this method, as you'll lose access to your coins!)

so, just like bitcoin paper wallet, except the final step of importing the paper wallet back to hot wallet in case of wanting to use the tokens, that is needed to be done by a proper omni wallet.