Does receiving chemotherapy intravenously during the daytime in Ramadan break the fast, and is it permissible for a sick person to break their fast to take medication when necessary, and what is the expiation if she breaks her fast?

Intravenous injections during Ramadan do not invalidate the fast. If it is possible to take the medication accompanying the injection at night, that is preferable. However, if it is necessary to take it during the day to avoid an illness or its worsening, then breaking the fast is permissible, and one must make up for those days. If one is unable to make up for them, then one must feed a poor person for each day.