How does this work?

[Anthony Boyd-Bey]

I am attempting to respond to an ad on craigslist but can't beacause my
sister has her name in the box how do I change it to my name

 

[Gary VanderMolen]

Your computer or your sister's?
You can't go changing the defaults on someone else's computer.
Sounds like you two need to each have your own Windows user
login, so you both can customize to your heart's content.
As a workaround, instead of clicking on the link in Craigslist,
copy it, then paste that email address into the 'To' line of
your own webmail.