Nick Cave, Henry Mancini, The Cramps, John Zorn etc.
I am a:
Welcome to the forum. I think the key is irrelevant. All he is asking is where he needs to start, for him just knowing if you're male or female would obviously help. It can aways be changed later. And please don't buy anything!, there are free apps everywhere. As worrying about the scale, don't, you can sing any notes you want but if they don't fit the melody then you're Yoko Ono.
Maybe submit your lyrics here and let some of the talented people here have a go at it. I'm also a newb but I've worked hard to research and find resources so stick your toe in the water and see if you're ready to jump in. Good luck.
Melodyne is a useful tool for pitch correction, though there are free alternatives as TBG pointed out.
But you don't need it just to find out what notes you are singing (and therefore which key). You could hit notes on a keyboard (real or virtual) until you find the closest one.
The person you sent the acappella recording to should be able to do the same.
If you can identify the chords then that can be helpful as many songs start and finish on the root chord of the key. So if the song starts on a G chord there's a good chance it is written in that key - though not a guarantee.
As RDM said, you don't need something like Melodyne. If you are not a musician you need piano or guitar lessons, or maybe a basic vocal music class.
Your "someone" probably did understand that what you sent to them was just lyrics and they made the assumption that it was already worked up into a song. That's why they asked what Key it was in. There are a lot of musicians that will collaborate with lyricist only folks and will put your words to music. You just need to be clear of what you are wanting from them.
Good luck and welcome to the forum. Good to have you here!
Last edited on Tue May 26th, 2020 12:04 am by moptop
JAPOV wrote: Play the first 3 note changes in your melody as a chord You really need someone who's a competent reader to explain keys properly. Rock musicians (me included) will often refer to the opening chord of a song, or the most dominant chord as the key. This isn't really correct, but it's usually enough to get things across. It matters more if you are working with musicians who are predominantly readers, say in an orchestra or a choir.