Link to imported meta-data: open attached file

Hello,

In user manual, it looks possible to open an attached file using a text field filled with XML file.

On my template, this field does not appear as an hyperlink, despite same coding as in example.

Question 1: does it mandatory to have [hyperlink=“xxxx.com” ] has to be in XML file to have the text field appearing has hyperlink?
Question 2: does the attached file has to be .pdf?
Regards