To send to a multisig address, just put in the destination field a multisig (m of n) address with this format: n_address1_address2_m
In order to set up your own multi-sig address, you do the following:
- Create 2 or 3 addresses in Counterwallet
- Make a regular transaction with each of these addresses, so that the pubkey of each address is visible on the blockchain.
Then you be able to add these as a multi-sig address here (following the same format 2_address1_address2_m or 3_address1_address2_address3_m):
Now you can use your multi-sig address like a normal address to make a (or any type of) transaction. However because it is a multi-sig transaction, you will get an unsigned raw transaction. In order to broadcast it, you will need to sign it with each address (varies based on your chosen m-of-n).
You can use the "sign transaction" action for each corresponding address that is required to make it valid.
Quoting this in case anyone missed it.