- To use Woocommerce easy checkout field editor in WPML mode ,  make sure you have these 4 plugins activated. 

WPML Multilingual CMS,WooCommerce Multilingual,WPML String Translation and WPML Translation Management 

- Then visit WPML/Theme and plugins localization menu and check "woocommerce easy checkout field editor " and click on "scan the selected plugins for scan" button. 

- Now visit WPML/string translation and click on "Translate texts in admin screens" link at the bottom. 

- There search for pcfme_billing_settings,pcfme_shipping_settings, pcfme_advanced_settings and pcfme_extra_settings and check the fields you want to translate. Then apply the changes. 

- Now visit WPML/String translation and translate your strings there.