Denim jackets are something that has a long history and somehow it maintained until today.
First created for the working class and after that worn by westerns; its made its way through rebels, punkers and hip-hoppers and until today where almost everyone has at least one denim jacket.
The pout of the jacket is that it is not so formal, but that is also what is great about it.
You can mix it with a dress if you want to be more feminine, but you can also combine it with more denim, for example, jeans, and be more of a rebel. Of course heels, converse, sandals and almost everything is compatible, it just depends on your style and imagination.