Bookmark does not appear in Acrobat DC (not in the view or navigation pane, just nothing)

hey, i just saved my word file to pdf. My word file has headings, acrobat does not recognize so I decided to create again in acrobat dc. The problem is there is no bookmark option in navigation pane. I search all online but I couldn't find it. The dc can open already bookmarked old pdf, and bookmarks section is available when I open it. But every new document I created, I can not use the bookmarks. Could you please help?