"Happy anniversary" is a common way to say "一周年快乐" in English. This phrase is often used to celebrate the anniversary of an event or special occasion, such as a wedding anniversary or the anniversary of a business. Some example sentences of this phrase in use are:

"Happy anniversary to my amazing husband. I can't wait to celebrate many more anniversaries with you."

"Congratulations to our team on our company's 10th anniversary. Here's to many more years of success."

"Happy anniversary to my parents, who have been happily married for 30 years. You are an inspiration to us all."

The origin of the phrase "happy anniversary" is likely rooted in the Latin word "annus," which means "year," and the English word "happy," which means "feeling joy or pleasure." When these two words are combined, they create a phrase that is used to express joy and happiness on the occasion of an anniversary.