HTC One (M8) for Windows
View SIM Card Number - HTC One (M8) for Windows
View SIM Card Number - HTC One® (M8) for Windows®
From the Start screen, swipe left to display the Apps list.
(located in the lower-right; may require scrolling to the bottom of the Start screen).
View the SIM ID.
You can also
remove the SIM card
then view the 20-digit SIM card number (with the gold contacts facing away).