If you do send it through to them, I would consider it quite risky to hold funds in a wallet that has been sent over the internet
You can now both control the coins, so neither of you have ownership since they could be moved by the other party at any time.
This is not how bitcoin works and it should never be this way either. You must send a transaction.
sometimes there is a need to send wallet seed instead of making a transaction and I can give some examples of that:
- Privacy: I do not want transactions to appear on the blockchain.
- Buying an old wallet: Maybe about tax reports and someone might want a wallet that contains coins from 2015.
- Claiming hardforks.
I could give more examples, but let's focus on that we want to send the seed words to a second party and all the conversations will take place in public.
You can use PGP encryption.
You can use the PGP encryption, it is one of the safest method
person's public key and encrypt your "message" that is the seed phrase with it and then send the encrypted result to them.
How? Suppose the wallet seeds are:
word1 word2 word3 word4 word5 word6 word7 word8 word9 word10 word11 word12