Make sure app/code folder is writeable.
Copy app folder from the zip archive to your Magento directory so that it merges with app folder of your site.
Logout and login back to get access to Web-forms > Settings page.
Go to Stores > Configuration > MageMe Extensions > Licenses page and enter your license number in WebForms Pro 3 License # field and click the Activate button.
If you have Varnish Cache server installed, please add /webforms* to cache path URL exclusions.
Get the latest version files from your account area My Downloads section.
Copy contents of the zip archive to your Magento directory so that the app folder is merged with the app folder of your site.
Execute console command: