Q: How can one send email to one's pc from one's iPad?

Usually by using the mail application and clicking Send.  Perhaps you should provide a little more detail about what you are trying to do. As stated, your question doesn't make much sense.

Just open the Mail App and create a new email to yourself.

As long as the account you are sending to is set up on the computer, it should receive the email.

Get help with Mail on iPhone, iPad, and iPod touch - Apple Support