Attributes are used to specify some properties related to WordPress content. E.g. it may be SEO title, tags or featured image.
As is mentioned here, the top content of document (.DOCX) is used for body. Other document’s contents that begin with strings marked as Word’s style “Heading 1” can used to set other attributes if the special option is enabled (see the picture below).
Mark body block as an attribute
To add or set attribute, we should type its name in a new string and mark it with Word’s style “Heading 1”. So the below content will be automatically applied to that attribute until meeting next attribute or end of the document. See the picture below.
Mark as an attribute lovely
The name of the attribute can be typed by using exact particular attribute name (e.g. tags or seo_title), or it can be typed by any text that we like but it should be bookmarked with a particular attribute name that mentioned above. See the picture below.