Hello, @JoHuCa,
Thank you so much for purchasing our theme and contacting our support center.
1) If you wish to add image icons to the menu is similar to the XStore demo, please navigate to Dashboard > Appearance > Menus > new all departments menu > Click on 8Theme custom link option > Menu option > there you may see the option Use img like, Choose/Select as image.
Please refer to the provided images here: https://postimg.cc/v4BdVW9q , https://ibb.co/hc74CXh and https://ibb.co/K038K1f. You are welcome to use any icon image in the image box as per your needs.
Additionally, you can watch a complete video for a better reference here: https://www.youtube.com/watch?v=7QluEYxznKs&list=PLMqMSqDgPNmCCyem_z9l2ZJ1owQUaFCE3&index=11.
2) To convert the English buttons into Vietnamese, we recommend using the Loco Translate plugin. You need to edit the language files of the Xstore theme and core-plugin. For a more detailed guide, please refer to the article provided in the link below:
Article: https://www.8theme.com/documentation/xstore/theme-translation/base-theme-translation/
We trust that this information will be of assistance to you.
3) Should you desire to modify the image and text in the payment method, kindly proceed to the wp-dashboard. From there, navigate to Appearance, then Widgets, and finally check the Cart area.
After that, Please navigate to Static blocks > All Static block > Here, you can edit the specific block according to your needs and publish it.
For your reference, an image has been provided: https://postimg.cc/PNW7vjpD
We trust this will address your concern.
If you have any additional questions or concerns, please do not hesitate to reach out to us. Our support team is always available to assist you.
Best Regards,
Team 8Theme.