iphone calender app

hellow

i am using iphone 6s' i have week call app for my calender and i dont get any notification

i read somewere that i need to go to iphone calender app and change there the setting of my google acount,

the problem is that on my iphone calnder app it dosent let me do anything on google acount and i cant change the setting there

plese help me

thanks