How to stop subscribe the iCloud

See this Apple article: Downgrade or cancel your iCloud+ plan

Downgrade or cancel your iCloud+ plan - Apple Support (PH)

or

Check your mail box and click the last Apple invoice you have recieved for you iCloud+ plan. 

Then scroll down & see:

👉 If you have any questions about your bill, contact support. This email confirms payment for the iCloud+ plan listed above. You will be billed each plan period until you cancel by downgrading to the free storage plan from your iOS device, Mac or PC.