Hello,
To change ORDER ONLINE OR CALL US (+1800) 000 8808 go to Appearance > Widgets > edit text widget in Left Top bar widget area.
To change Newsletter go to Theme Options > E-Commerce > Promo Popup Sign In or Create an account – you can change it using translation files. Hw to translate theme read here http://xstore.helpscoutdocs.com/article/30-base-theme-translation
Regards
