Quick Tip:
It is customary to add a honorary suffix to the last name of a customer or someone who you do not know well. Xiānshēng（先生）is for men and Nǚshì（女士）is for women.
Basic greeting:
早上好 (Zǎoshang hǎo) 约翰娜 先生/女士 - Good morning, Mr./Ms. Johanna
你好 (Ní hǎo) 约翰娜 先生/女士 - Hello/Good day, Mr./Ms. Johanna
晚上好 (Wǎnshàng hǎo) 约翰娜 先生/女士 - Good evening, Mr./Ms. Johanna