Hey Rashid, if you wish to send an email along with an attachment, you simply need to use "Send SMTP Mail Message" activity and use Attach PDF option to attach any file.
But to use SMTP mail service, you first have to configure the Port and Server in the Properties of Send SMTP Mail Message. Also create variables like Email and Password to store your email id and password.
To attach a file, click on Attach PDF and write the path of file you wish to attach. For reference, see the screenshot: