I used to work for a Language Service Provider (LSP). Typically it's used in marketing material, because a directly-translated slogan or message might might not 'work' in another language or culture. It might just sound bad or clunky, or it could even be offensive in certain contexts.
As others have said, the resulting text should convey the same meaning in the same tone, but needn't be word-for-word correct.
I've also translated and yeah, it means going from scratch and becoming not only the translator but the writer of the text. You show the client, "is this what you meant?" And THEN you translate THAT.
As others have said, the resulting text should convey the same meaning in the same tone, but needn't be word-for-word correct.