If she has a data allowance on your phone contract then she can find out on the phone where she can turn on data and use your mobile service supplier's network. Alternatively, if she is near a WiFi spot she can turn on WiFi instead, connect to the modem creating the WiFi, put in the WiFi password if needed, and use that.
WiFi is usually either free in public places; or if using your own connection is already paid for by you for your PC connection (unless you go over any allowance you might have). Data costs will be specified by your mobile service supplier.