If someone else set my ID and PW If I change PW do they still have access to my everything

Thank you so much for replying to my question. I did change the PW awhile ago. I didn’t want an i cloud but it was set up anyway. So I didn’t know if the new PWs would show in i cloud. I have an I pad now show it shows me more than the phone. One more question. I sign into iCloud and under My Devices. It’s says you are signed in and running iOS 8, Mac Yosemite, watchOS 1 or later on these devices. It said same thing on last new phone. Waited 2 yrs I bought this and the iPad. I’ve never owned any of those. Just phone now iPad and have iPods. I tried to take a picture. Thank you again!!

Thank you so so much! I have asked so many people and no one knew what that was or could answer my questions! The best!