Can't find the equalizer

Where do I find the equalizer

Assuming (as you’ve not stated which product) it has app support, then in the app.

Once you have the Soundcore product (whatever it is!) paired connected, then download the Soundcore app from your phone’s store (app store, Play store) and install, then “connect” in the app and see if it recognised your device. Then there’s an EQ setting.

Depends on the type of speaker /earbuds.
If these are added to the app there is an eq setting installed.
Otherwise not and you have to use the eq of your player.