How do i change the text Username to Email? Ive disabled loging in via Usernames

Hi there, nice plugin i think i might even upgrade to the premium version but i would need to be able to change the text that says Usrname to Email Because users can no longer log into my website via Usernames only email adresses, so i would also need to rename the reset password to just email instead of Username or email, please help me out with this as need to know how to do this before i even consider purchasing for the extra features thx.

https://www.ads-software.com/plugins/nice-login-register-widget/