Hello,
You need to create a checkbox custom field and then use the Joomla translation system in order to translate the field label.
in the Joomla translation, you will be able to put some HTML (but without double quotes, you need to use simple quote instead).
Otherwise, you can use a view override for the registration view and change the display of that specific field.
There, you can change the label (and put some HTML, thing that you can't do in the HikaShop field edition) and you could also see to do more than just a link but maybe a popup.
www.hikashop.com/download/languages.html#modify
www.hikashop.com/support/documentation/1...-display.html#layout
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.