What is the ruling on a woman plucking or shaving the hair of her legs and thighs, and is it permissible for her sister to do that for her?

The ruling on removing body hair has been previously addressed. If it is established as permissible, then it is preferable for a person to remove it themselves. If they need assistance from another, there is no objection to seeking their help, provided that the hair being removed is not in areas that are forbidden for the helper to see, such as parts of the 'awrah (intimate parts). Therefore, it is permissible for the questioner to seek her sister's help in removing hair from her lower legs and feet, but it is not permissible for her to remove hair from her thighs, as they are considered part of the 'awrah.