Where do you find "scriptures in the bible"?

Scripture refers to books in the Bible. There are 66 of them...Genesis to Revelation. They were written by men who were inspired by the Holy Spirit.

I think it's literally just a word created to reference religious writings.

I don’t sir.

All religions regard their writings as the word of God. "It is written" is an ancient phrase which means that it was prophetic and couldn't be disputed. If you don't believe it, it means very little.

Scripture refers to any religious writing.
In this case, the Bible is the main Christian scripture, though it is actually multiple separate scriptures put together into one, as they link chronologically, to show the full story.
That's why it's in segments, such as Genesis, Revelations, Leviticus, Exodus, etc.

Take this with a grain of salt as I am non-religious, but I did grow up with Christian parents. I'm 90% certain a scripture is just a Bible passage, however.