1. Install the plugin
Gravity forms 2.5 or later needs to be installed and activated to use this plugin!
Log in to your WordPress Backend and click on “Plugins” in the left hand menu. Next, click “Add New” and than click “Upload Plugin”

2. Enter your license details
Navigate to the plugin settings by clicking on settings on the plugin screen.

Enter your license key and press the activate button.

3. Set your default country
It is very important to set your default Tax country so the plugin knows where not the apply reverse charge VAT. You will find this setting on the plugin settings under the license activation section.

4. Add EU VAT field to your form
Lastly you need to add a EU VAT field to your form.
Read more about the EU VAT field here