src/Bootstrap/Elements/InputGroup.php
public function suffix($suffix, $isPlainText = true)
    {
        if ($suffix === null)
        {
            return $this;
        }

        $element = clone $this;
        $element->suffixes[] = [
            'content'   => $suffix,
            'plaintext' => $isPlainText,
        ];

        return $element;
    }
public function suffix($suffix, $isPlainText = true)
    {
        if ($suffix === null)
        {
            return $this;
        }

        $element = clone $this;
        $element->suffixes[] = [
            'content'   => $suffix,
            'plaintext' => $isPlainText,
        ];

        return $element;
    }
Add an addon after the field

@param string|\Spatie\Html\BaseElement $suffix      One or more suffixes to append before the field
@param bool                            $isPlainText Is the prefix to be handled like a button, dropdown, etc.

@return static