After you sign up on Roblox, should verify your email for important purposes. Although you can play games without it, but I think a lot of the features of roblox.com will be emailed to roblox player, for example another case if you want to join the Builders Club your account should verified by a valid email.
To verify your e-mail on Roblox there are 2 methods:
1. via Account Settings
Login to roblox.com go to settings menu
Just update your email address and click Save.
You will receive an email confirmation from www.roblox.com
Click on that verification link and done. Your account has been verified now.
2. by sending email to Roblox Staff
You can verify your account by sending an email to Roblox’s Email: firstname.lastname@example.org
Here’s an example what you have to write to them:
I would like to verify my son/daughter’s email
Birthday: November 5 1998
Wait for a reply from them. Ok. see you.