What type of sentence is this The girl in the corner wearing blue dress?

That's not a complete sentence. It's a phrase that acts as a noun phrase. It describes a girl, but it doesn't have a verb, which is necessary to make a sentence.

To make it a sentence, you would need to add a verb. For example:

* The girl in the corner wearing a blue dress is smiling.

* The girl in the corner wearing a blue dress is reading a book.