I never recieved my refund for last year.why did i get a paper in the mail saying i need to verify my identity? Ive never been asked of this before

Is it an IRS Letter 4883C?

Yea

I got one today

Wht happen

What you have to do or what was done.
Did yoj get your refund

See this IRS website for a IRS Letter 4883C - https://www.irs.gov/individuals/employees/understanding-your-4883c-letter

And this IRS website in regards to Identity Theft - https://www.irs.gov/individuals/how-irs-id-theft-victim-assistance-works