「かしこまりました」 is an extremely polite way of saying "Certainly," "I understand," or "Understood." It is primarily used in business settings, hospitality (by shop or restaurant staff), or when speaking to a superior to show respect and acknowledge an instruction.

ビジネスシーンや接客業などで、上司や顧客の指示・要望を承諾したことを伝える極めて丁寧な表現です。「わかりました」の謙譲表現に当たります。