Paper lid is made of kraft paper, cardboard, grey board, which is the most common lid option for paper tube packaging.
The lid could be either flat or rolled-edge (also called curl and disc)
Metal caps, usually made of tinplate material, is a food grade lid option for paper tubes,
Tinplate lid carries premium air-tightness, and is most frequently used for wine, liquor and spirits packaging, foodstuff like protein powder, herbs, loose leaf tea packaging
Plastic lid is not food grade, and not intended for direct food contact.
Very often it is used for poster tubes, shipping tubes, mailing (mailer) tubes, and packaging tubes