There’s a simple way to tell if your mailbox has the plus + address feature.
Plus email addressing (aka disposable or sub-address) is sometimes available automatically (Gmail or Outlook.com) or has to be switched on (Microsoft 365 hosting).
Some other mailhosts might have an option to allow plus + addresses for your mailbox.
Search your mailbox host support or just web search for your mailhost name with ‘plus email address’. Or just try a test Plus address email ([email protected]) and see what happens.
Send a test + email
If you think your mailbox has plus addressing, test it before handing out plus addresses to other people. Just to make sure it’s all working as expected.
From a different mailbox, send a message to yourself with a plus address extra e.g. [email protected] . If that message arrives OK, then you’re good to go.
If it’s not setup, the message should ‘bounce’ with an ‘unknown user’ type error.
No need to test each plus address you use … just a starting ‘one off’ test.
Yahoo doesn’t have plus + address but do have a form of ‘disposable’ email address.
These separate addresses use a hyphen – separator AND have to be individually setup in advance.
See Yahoo mail for details.
How to get ‘Plus’ email addresses, the new feature in Microsoft 365 and Outlook.com
What are email Plus addresses and how to use them
Get the most from Plus addresses in Outlook
What can you put in your email address?