There is a noun for "receive": reception.
What about "send"? Is there a noun for this verb?
It's about sending SMS messages, so I wish to underline the outgoing nature of the message.
I agree with bib. Transmission is probably the best comparison here. Transmission comes from the Latin noun transmissio, which comes from the Latin verb mitto (mittere) meaning I send (to send).
Possible nouns linked to send, are 'conveyance' or 'consignment'. One can, also, rather than 'send' the goods, 'consign' them.
And that of 'receive', in the case of goods is not 'reception' but 'receipt'. I find myself 'in receipt' of letters and goods, never in 'reception' of them.
I am however, from time to time in 'reception' of visitors.
So I think it's 'receipt' for goods, 'reception' for people.
It depends on just what is being sent. A letter once sent becomes a missive, a word built on the soundest of etymological foundations.
But if you prefer epistles over letters, we may have to fish from a different etymological lake.
In some contexts, you can use "emission".