What does offer mean? In the workplace?

Letter of appointment and letter of admission.

At present, there is no unified name for offerletter. Some people call it "the letter of admission", some people call it "the letter of employment" and some people call it "the invitation letter". In the past, it was generally said that a foreign company or a foreign school sent a letter in a similar format, expressing its willingness to be hired. Later, many people received their own "offerletter" from the company and called it a telephone offer. When they were informed by the company that they were qualified for the interview, they said that they had received the offer, but the real offerletter was just a very formal big enterprise.