Is it permissible for a divorced woman to participate in charitable activities, given that she is retired, in debt, and supporting three children?

If participation in charitable acts means donating money, then voluntary charity (sadaqah tatawwu') is not permissible if it affects the fulfillment of obligatory debts, because what is obligatory takes precedence over what is voluntary. However, if it is possible to combine paying off debts and giving charity, then there is no harm in that; rather, it is commendable. It must be noted that performing good deeds is not limited to spending money; rather, it includes glorifying Allah (tasbih), exalting Him (tahlil), enjoining good, forbidding evil, and all other avenues of righteousness.