The Blogger tool (unlike Google Sites) doesn't have the facility to attach documents.
Fortunately, you can create a public folder for documents on Google Drive, and link to it from your blog.
Here is a step-by-step guide to how to do that.
Step-by-step guide: Creating a public folder
You only need to do this once for any group of documents associated with a particular site or project.
- Open Google Drive and click on the NEW button.
- Select Folder
- Give your folder a name and click CREATE
- Right-click on your newly-created folder and select Share...
- Click on Advanced
- Click on Change...
- Select 'Public on the web' and click SAVE, then DONE
Uploading a file
Next, you need to upload the file you wish to publish to your folder. You should avoid uploading Word documents for use as forms; use Google Forms instead.
- Open Google Drive and double-click on the public folder you created.
- Click on NEW and select File upload
- Browse to the file you want to upload, select it, and click Open
- The file will now be uploaded to your public folder. Right-click on it, and select Get shareable link.
- Click on the link in the pop-up dialogue to select it, and press Ctrl C on the keyboard (to copy it to the clipboard)
Creating the link in Blogger
- In your blogpost or page, highlight the text that you want to be the link (don't use "click here" or "here", use something meaningful like the title of the document) and click on the Link button
- Paste the URL (web address) that you copied in Step 5 above into the "web address" box and click OK.
- Finish editing your blogpost and Save for later, or Publish.