How long does it take to apply for an invitation letter, and what is its validity period?

The application process usually takes around 3 to 10 working days, depending on the type of invitation letter and the specific application circumstances. The validity period of a business visit invitation letter is typically 30 to 90 days, and extensions can be requested based on actual needs. The validity of a work visa invitation letter is usually tied to the duration of the employment contract, generally ranging from 1 to 3 years. For family visit invitation letters, the validity period is typically related to the main applicant's visa validity, usually around 1 year. (Adam)