you have to signin for every service online, with 10minutemail.com you don’t need to provide your own/private mail account, it creates a valid random account for about (for sure) 10 minutes, the provider explains
sign up for a site which requires that you provide an e-mail address to send a validation e-mail to. And maybe you don’t want to give up your real e-mail address
check out https://10minutemail.com

as same as for mail it is also available for sms, your don’t have to provide your personal phone number, e.g. send any verification code to one of the free available numbers
try it: https://www.receive-sms-online.info/
