A companion to signed-out Ads Settings
It's most common to turn Google ad personalization on or off with Google's Ads Settings. These settings are saved to your Google Account (if you're signed in), or to your browser (if you're not signed in).
Alternatively, you can install a browser plugin to keep your preference to opt out of personalized ads.
Turning off ad personalization doesn't remove ads
If you use this browser plugin, the same number of ads will appear on websites you look at. The plugin turns off ads personalization. Turning off personalization makes ads less relevant to you.