Hello,
Thank you very much for choosing our theme and for contacting us.
1. You can translate/rewrite all theme and plugin texts via PO file in WordPress. Here is a video tutorial that should help you translate your website texts with a Loco Translate plugin https://www.youtube.com/watch?v=D3NsDdMzsls&list=PLMw6W4rAaOgKKv0oexGHzpWBg1imvrval&index=3
Please check the video tutorial to see how to save the translation file correctly. You can remove the plugin and translations would remain. Also, translations would remain after each theme update.
The title widgets are not translated with the Loco, please navigate to Appearance > Widgets > Shop page widget area and enter the widget and replace the title.
2. I am checking your site and I see the newsletter popup window appears, what do you mean, please? Newsletter is provided by the MC4WP: Mailchimp for WordPress plugin. You need to integrate the account. Please check the plugin documentation https://www.mc4wp.com/kb/#utm_source=wp-plugin&utm_medium=mailchimp-for-wp&utm_campaign=plugins-page or clarify the issue. The popup window is enabled and configured in the Theme Settings > Shop > Promo popup.
3. Please provide the page URL with the problem. I cannot catch the problem.
Best Regards