I responded to you via email, but in case others want to see here is what I sent.
We are reworking parts of the plugin to make translating these fields easier, however in the meantime you can perform the following steps:
1. Move the existing Gift Card product to the Trash (it will need to be recreated using the translated values).
2. Download the wp-config.php from your FTP server.
3. Keep a backup of wp-config.php in case there are problems.
4. Edit wp-config.php and scroll to the end and add the following bit of code:
Scroll towards the bottom, and before the line that says “Happy blogging.” add this code ABOVE that line (translate as needed):
define( ‘PWGC_DENOMINATION_ATTRIBUTE_NAME’, ‘Gift Card Amount’ );
define( ‘PWGC_OTHER_AMOUNT_PROMPT’, ‘Other amount’ );
define( ‘PWGC_GIFT_CARD_NUMBER_META_DISPLAY_NAME’, ‘Gift Card’ );
define( ‘PWGC_TO_META_DISPLAY_NAME’, ‘To’ );
define( ‘PWGC_FROM_META_DISPLAY_NAME’, ‘From’ );
define( ‘PWGC_MESSAGE_META_DISPLAY_NAME’, ‘Message’ );
/* That’s all, stop editing! Happy blogging. */
5. Save the wp-config.php file and re-upload it to your server.
6. Click on WooCommerce -> PW Gift Cards -> Create the Gift Card Product.
If you have any problems, replace wp-config.php with your backup file.
Let me know if you have any questions!