At least 18 years of age.
As stated in the Tasker Terms Of Use: You must be at least 18 years old, are of legal age to form a binding contract with Frictionless in the jurisdiction in which you reside, and are otherwise capable of entering into binding contracts.
For more information, please take a look at this help center article: Can I let someone else use my Hyer account/login? Can a minor use the Hyer platform?