Can't add icons to home screen I have an ASUS ZenPad 3S 10 (Z500M, model P027) and I can't add any shortcut icon from the app drawer to the home screen by pressing and dragging.

I know I used to have this option, but now something has changed and prevented it.
The issue might be that the launcher layout is locked. Try to remove or replace an icon already present in launcher and if you can't move the icon, then most likely the layout is locked.

To turn off the option, the ways are different in different launchers, try going to launcher settings and find option to lock the desktop layout or something similar and turn it off.