Forgot Apple ID

my mobile iphone 7 ios11 no pta prof jast i resat mobile than on but not activate i try to 3 days but mobile on an opasn (unable to activate an update is required to activate your iphone) lear more at apple.com. /uk/support) this isshu caret and me to mach deshart so pls solvd isshu and i forgate icloud

[Re-Titled by Moderator]