Edit Login Form - Change Username to Email

-- HikaShop version -- : 3.2.0
-- Joomla version -- : 3.8.0

For some reason I cannot find how to change or edit "Username" on the login form.

I want to change it to "Email/Username" as users can login with their email address.

Thanks!

So I tried Joomla's language file and Hikashop language file before posting my question. So based on your answer I am assuming that it's hikashop language file where I have to make the change. I changed the below "HIKA_USERNAME="Username" but it still does not change.

What am I missing please?

;joomla 1.6
HIKA_CONFIGURATION="Configuration"
HIKA_CATEGORIES="Categories"
HIKA_HELP="Help"
HIKA_COPY="Copy"
HIKA_DELETE="Delete"
HIKA_USER="User"
HIKA_EXPORT="Export"
HIKA_NAME="Name"
HIKA_EDIT="Edit"
HIKA_SAVE="Save"
HIKA_CLOSE="Close"
HIKA_FILES="Files"
HIKA_APPLY="Apply"
HIKA_USERNAME="Email/Username"

Thanks Nicolas.

It was another login form and I was assuming that it from Hikashop and not Joomla that's why I couldn't find it.