Where Im can find file to translate this words ? I already check all checkout.php and shipping.php
To edit Estimate Shipping & Taxes, Country, Region / State, Post Code text
Go to catalog/language/english(your language)/checkout/shipping.php (for oc version 2.0.3.1 and below OC versions)
Go to catalog/language/english(your language)/total/shipping.php (for oc version 2.1.x)
You can see following code will be present
$_['heading_title'] = 'Estimate Shipping & Taxes';
$_['entry_country'] = 'Country';
$_['entry_zone'] = 'Region / State';
$_['entry_postcode'] = 'Post Code';