If you are clueless as to how to change gmail password on your iPhone, then you can follow the steps mentioned here. First of all, open the Gmail app on your iPhone or iPad. Then, in the top right, tap your profile picture or initial Manage your Google Account. If you don’t use Gmail, go to myaccount.google.com. After that, tap Personal info at the top. Under "Profile," tap Password and enter your new Password, then select Change Password.