Microsoft Word 2016 applying styles and text being placed in text box with anchor

I have recently started a new business and have had a template Microsoft Word 2016 document prepared for me to use as headed note paper. There is an image in the header.

I have been modifying the Header styles (e.g. Header 1, Header 2 etc.) - which is all fine. However, when I apply a chosen style (e.g. Header 1) to the text, it seems to place a text box around the text - why?!

There is also a blue anchor next to the text box.

Can anyone please help me?

Many thanks