In the Tumblr Editor, open your Account Settings and select Edit Appearance.
On the next page, select Edit Theme.
Click on the Edit HTML link.
Paste this exact script into your Tumblr HTML file. It's best to add it between the Head tags. Then update and save.
Create Text Post
Return to your Tumblr Admin page, and create a new Text post.
Paste this shortcode into the post and save. You'll see the new POWr Order Form plugin when you expand the post. Click the POWr Settings Icon to set up POWr Order Form.
Edit your Order Form on Tumblr:
Go to the live Tumblr website and click the settings gear in the top right corner of your Order Form Plugin.