Customeryf.info is an adware that will attempt to commandeer your browser search and homepage. Once you click allow the adware to send you notifications, it will bombard you with pop-up ads sending you to malicious websites to get money from you or infect your computer further like slowing it down. It may also prevent you from changing your settings back.
Customeryf.info is usually installed through bundled software clicked from spam emails, freeware, or fake updates without you knowing. You have to remove it immediately.