每 + 天 / Number + 天
天 (tiān) serves as both the word for "day" and as a measure word for counting days. When preceded by 每 (měi, "every"), it forms 每天 meaning "every day" or "daily." It is one of the few time nouns in Chinese that doubles as its own measure word, requiring no additional classifier.
我每天早上六点起床。
Wǒ měitiān zǎoshang liù diǎn qǐchuáng.
I get up at six o'clock every morning.
他在北京待了五天。
Tā zài Běijīng dāi le wǔ tiān.
He stayed in Beijing for five days.
每天坚持锻炼半小时对身体很好。
Měitiān jiānchí duànliàn bàn xiǎoshí duì shēntǐ hěn hǎo.
Exercising for half an hour every day is very good for your health.