src/Money.php
public function formatWithSign(bool $displayCountryForUS = false): string
    {
        $string = $this->format($displayCountryForUS);

        if ($this->amount <= 0) {
            return $string;
        }

        return '+' . $string;
    }
public function formatWithSign(bool $displayCountryForUS = false): string
    {
        $string = $this->format($displayCountryForUS);

        if ($this->amount <= 0) {
            return $string;
        }

        return '+' . $string;
    }
The same as format() except that positive numbers always include the + sign

@param bool $displayCountryForUS Set to true if you would like 'US$' instead of just '$'
@return string