Word Excel 2016 issues

libra10

I have a long document, and keep seeing the following triangular mark, the line is my cursor.  Also the document is in Compatibility mode.
Can anyone advise how to remove the marks and revert to an ordinary document?
Thank you

Neil_Jones

This may be the ability to collapse part of the document if you've used the headers:

https://support.microsoft.com/en-ie/office/collapse-or-expand-parts-of-a-document-701786e0-95e2-40bf-bfe5-f0233cd3520c

libra10

Thank you for the information.
The document isn't all that long, about 5 or 6 pages.  Will have a good read, and check whether it solves the problem.
Much appreciated.

libra10

Thank you very much Neil_Jones - now sorted.
Best wishes