Vanguard old school = all new accounts were mutual fund only. No stocks, ETFs, etc. These were NOT brokerage accounts. This applied to taxable, IRA, Roth, etc. If you wanted brokerage capabilities you had to make a special request.
Vanguard now = all new accounts are brokerage accounts. You can trade mutual funds, stocks, ETFs, etc. This applies to taxable, IRA, Roth, etc. If you want a mutual fund only account you need to make a special request.*
You likely have an IRA brokerage account. No biggie. It's still an IRA, but you can buy stocks and ETFs.
* The only reason I can see requesting a mutual fund only account would be if you worked in the investment industry and your employer[or the SEC] didn't want you trading individual stocks in an account they couldn't monitor[insider trading concerns]. Having a Vanguard mutual fund account would let you buy Vanguard index funds, but you wouldn't be able to trade individual stocks.