您需要使用Python编写脚本来完成此任务。以下是示例代码：

import smtplib
import os
from email.mime.multipart import MIMEMultipart
from email.mime.application import MIMEApplication
from email.mime.text import MIMEText

def send_email(email, password, to, subject, body, attachment_path):
    # 创建MIMEMultipart对象并设置邮件头信息
    message = MIMEMultipart()
    message['From'] = email
    message['To'] = to
    message['Subject'] = subject

    # 添加邮件正文
    body_text = MIMEText(body)
    message.attach(body_text)

    # 添加附件
    with open(attachment_path, 'rb') as f:
        attachment = MIMEApplication(f.read(), _subtype='pdf')
        attachment.add_header('Content-Disposition', 'attachment', filename=os.path.basename(attachment_path))
        message.attach(attachment)

    # 发送邮件
    server = smtplib.SMTP('smtp.gmail.com', 587)
    server.starttls()
    server.login(email, password)
    text = message.as_string()
    server.sendmail(email, to, text)
    server.quit()

# 设置发送邮件的参数
email = 'example@gmail.com'
password = 'mypassword'
to = 'receiver@example.com'
subject = 'PDF file'
body = 'Please find the attached PDF file.'
attachment_path = 'path/to/myfile.pdf'

# 调用send_email函数并发送邮件
send_email(email, password, to, subject, body, attachment_path)

此代码将创建一个MIMEMultipart对象，并添加正文和附件。当添加附件时，代码使用MIMEApplication对象将文件添加到邮件中。此方法还包括使用smtplib库连接到SMTP服务器。在这种情况下，我们连接到Gmail的SMTP服务器。最后，我们调用sendmail方法将电子邮件发送到收件人的电子邮件地址。