My FDW has asked for Wifi password. I am not comfortable giving it as she is already on the phone all day long - I work full time, so hard to limit phone time). She has internet through her phone. What do you all do?

I use my phone when I am at work. As long as I get my job done and correctly prioritise work over answering a non urgent Facebook posts, for example, my boss has no concerns. Treat your employee with the same respect that you wish to be treated with. If she's not getting her job done because she's on the phone all of the time, speak to her like an adult, the same way that you would like your boss to speak to you should your work be deemed to be suffering.