I just got my password on my pc i have a ipad and a tablet can i use the same.password on these?

Yes. But don't. A hacker could breeze through all your passwords, including your iTunes. No one wants that.
You can always set up a system for how you set your passwords. Like "specialpassword" + 4 characters of device or website + 4 digits because all these websites are annoying about using digits. Your laptop password would be "specialpasswordlapt2014", iPhone "specialpasswordipho2014", Amazon "specialpasswordamaz2014" and so on.