News just came out that provided an update from the Yahoo data breach that was disclosed last year. The number is no longer 1 billion accounts compromised, it is now reported being all 3 billion accounts.
With the assistance of outside forensic experts it was determined that ALL of Yahoo’s user accounts were affected by the hack. Names, birth dates, phone numbers, and passwords were all potentially exposed. Even security questions and backup email addresses were compromised, so hackers could reset passwords.
It is likely that many people use the same passwords on different accounts, and therefore run the risk of having other accounts compromised. If you didn't change your Yahoo password back in 2016 you should absolutely do it now. It is also recommended that you change it anywhere else you may have used that same password. You may want to even unlink your mobile device from your Yahoo account and relink it using a new password and/or turn on two-factor authentication.