Cant do a search suggestion in header

I am doing an ecommerce with a search in the header through a text field, when the user make a search, an iterator with the suggestions is displayed but when the header is displayed it is as large as the iterator.
In summary, an object cannot share the header and the body of a page.
I watch a lot of example search custom with iterator but none in the header, but i see an app that has this funcionality.