What does ¿cuál es la fecha del día de la independencia? mean and how would you reply?

For this case the translation of the question in English is given by:

What is the date of Independence Day?

The answer to the question will depend on the country where you are located.

For example, if you are in the United States, your answer is:

Independence Day is July 4 of each year.

The translation of the answer in Spanish is:

El dia de la independencia es el 4 de julio de cada año.

What is the date of Independence Day?

Independence Day is July 4 of each year.