Hello,

No, we did not use any html block. That content inside the description tab designed with the help of Wp-Bakery Page builder. You can also use all the Wp-Bakery elements inside the tab. Just edit any of your product with Wp-Bakery Page builder as in the below screenshot:
https://jmp.sh/6RmPhCE

You can use 3 column or more then 3 if you want. Just simply select the column structure from here:
https://jmp.sh/vhwfLWB

Best Regards.