Understood from below links which it is limitation of Qlik Sense during download visualizations where sheet titles, filter panes and widgets cannot be exported.
https://help.qlik.com/en-US/sense/June2020/Subsystems/Hub/Content/Sense_Hub/Printing/exporting-visua...
Although we have workaround to have the titles appearing the PDF whenever there is a download activity happen in the dashboard, however, we do hope to suggest the sheet titles can be included during visualizations download as PDF files.
Thanks and appreciate if this idea is accepted.
Regards
Shokyee