@SoarKoHa first, Brave Ads is not available yet for Vietnam users.
Brave Ads is geo-restricted to US, Canada, German, France, and UK, for now. See FAQ: Why am I not seeing Brave Ads? and Please explain why ads are not available everywhere
I’m not sure why you able to enable Brave Ads. Maybe it’s a bug. cc @Mattches @gsarvadnya
And current type of Brave Ads is not shown on website. But it’ll appears as system notification. Likely you saw YT ads – the one from Google.
More https://brave.com/brave-ads-launch/
An example of Brave Ads (copied from blog post linked above)
Thanks