WordPress at a glance
function is not described

PHPMailer\PHPMailer

PHPMailer::setWordWrap() public WP 1.0

Apply word wrapping to the message body. Wraps the message body to the number of chars set in the WordWrap property. You should only do this to plain-text bodies as wrapping HTML tags may break them. This is called automatically by createBody(), so you don't need to call it yourself.

{} It's a method of the class: PHPMailer{}

No Hooks.

Return

null. Nothing.

Usage

$PHPMailer = new PHPMailer();
$PHPMailer->setWordWrap();

Code of PHPMailer::setWordWrap() WP 5.7.2

<?php
public function setWordWrap()
{
    if ($this->WordWrap < 1) {
        return;
    }

    switch ($this->message_type) {
        case 'alt':
        case 'alt_inline':
        case 'alt_attach':
        case 'alt_inline_attach':
            $this->AltBody = $this->wrapText($this->AltBody, $this->WordWrap);
            break;
        default:
            $this->Body = $this->wrapText($this->Body, $this->WordWrap);
            break;
    }
}