“Production” is sold as one word and bought as one word, and it covers three different jobs that happen at three different times. People discover which one they actually bought when they ask for the finished file.
What production is
It is the stage where the song becomes a recording.
Composition and arrangement. Deciding what the song is made of: the parts, the instruments, where it builds and where it gets out of the way. An arrangement built around a template is why a lot of records sound like other records.
Programming and session playing. Actually making those parts exist, whether programmed or played.
Recording. Capturing performances properly, which is mostly about decisions made before anyone presses record.
Vocal production. Directing the take, comping the best passes, tuning where it needs it, deciding the doubles and the phrasing. This is usually where the time goes, because a listener forgives an arrangement long before they forgive a vocal.
Production ends with a song that exists: arranged, recorded, and sitting as parts in a session.
Where it stops
It stops before the record is balanced.
Mixing takes those parts and makes them one thing: levels, space, tone, the decisions that turn a folder of recordings into something that sounds intentional.
Mastering takes the mix and prepares it for release: final level and tone, and consistency with everything else it will sit beside on a playlist.
These are separate crafts with separate skills, and they are priced and scheduled separately. Plenty of people sell all three as one engagement, and there is nothing wrong with that as long as the agreement says so plainly. What causes arguments is a quote that says “production” and a client who assumed it meant “finished”.
Why the boundary matters to you
Three reasons, and only one of them is about money.
Scheduling. Mixing cannot start until production is done. If both are on one timeline and the arrangement slips, the mix slips with it, and the release date was set against the mix.
Revisions. A production revision changes what the song is made of. A mix revision changes how those parts sit. They are not interchangeable, and an agreement offering “revisions” without saying which is offering something undefined.
What you are actually buying. If you already have a recorded arrangement with performances you want to keep, you need mixing, not production. Paying for production and receiving a remake of a song you were happy with is a common and expensive misunderstanding.
The question worth asking first
Send the song and ask which stage it needs. An honest answer sometimes costs the person answering a larger job, which is exactly why it is worth asking.