Google’s Gmail and G Suite have “plus addresses” such as daniel+test@gmail.com
Microsoft’s Outlook.com (formerly Hotmail) added plus addressing back in 2013, and Microsoft enabled the plus notation for Microsoft 365 and Exchange Server in late 2020.
cPanel added support for plus addressing in 2019.
Plus addressing for email, also known as “subaddressing”, allows you to create unique, receive-only email addresses that are extensions of your actual email address. The syntax for plus addressing is <local-part>+<tag>@<domain>. For example, if your email address is daniel@outlook.com, you can use daniel+newsletters@outlook.com as a plus address. The original email address must be valid, and the +tag value you add is arbitrary, subject to regular character restrictions for SMTP email addresses12.
Use this plus addresses feature to manage/filter/route email for your site registrations, newsletters, subscriptions, etc.