I finally got it !!!
Thank you so much guys !
void ABoss_Character::getPlayerPosition() {
FVector MyCharacterPosition = GetWorld()->GetFirstPlayerController()->GetPawn()->GetActorLocation();
GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Blue, FString::Printf(TEXT("Player Location: %s"), *MyCharacterPosition.ToString()));
}
This is the function in case someone needs it in the future