The phrase “how long does it take” refers to the length of time needed to perform an action.
A: How long does it take to travel from London to Coventry?
B: It takes an hour by train.
A: How long does it take you to build the garage?
B: I guess it’ll take me about a week.
The phrase can be asked in the present, future and past tenses:
A: How long does it take them to prepare dinner?
B: It takes them an hour.
A: How long did it take them to get to Oxford?
B: It took them 2 hours.
A: How long will it take them to pack their bags?
B: It will take them half an hour.