While logged in, select the page to which you would like to add file attachement.
Click the Edit tab on the top of the page.
Look for File - add a new file.
Browse for the file you want to upload, then click Upload.
Uncheck Display if you don't want the file to appear in a list at the bottom of the page. However, this can be useful if you want to upload a series of files and have the automatically appear as links on your page.
If you want to make a text link to your file, right click on the blue image file name to "copy link address" of your uploaded file.
Type in the text for the link to the file in the Body field and highlight that text.
Select Insert/Edit Link (photo of the chain-links).
A popup window will appear with a Link URL field.
Use the relative URL for the link to the file - /sites/default/files/myfile.doc. By using relative links, the website can be moved to another server without breaking the links, and there are no https issues in some browsers.
Choose the Target - either to open the file in the same window or in a new window.
The Title is what the user sees as the cursor hovers over the link.
Click Insert to insert the file link on your webpage.
Preview then Save the page to save your work.
Check to make sure the link works as you expect it to work.