Are you starting with a Microsoft Word document? If so, you can save a Word doc as a PDF by:
Click on the File (upper left corner) then Save As, then look near the bottom of the page and you should see Save as Type: and it defaults to Word Document but you will see an drop down arrow on the right side of that box. Click on that drop down arrow and look for the PDF choice.
I apologize if this seems ridiculous but you don't say what type of document you are starting with. It would help to know that...so we have to start somewhere. Once it is saved as a PDF, you can attach it to an email and send it to your intended recipient. You can also do that with a Word document. What you may be facing is a size issue. If the file is too large for your Internet provider (some limit the file size to 1mb or less), than that is another conversation.