To be able to take out a loan, you must be at least 18 years old. Otherwise, all types of borrowing (consumer loan, mortgage, line of credit, etc.) will be prohibited for you.
However, there are certain special cases. If your child is 16 years or older, you can act as a guarantor for them to obtain a loan.
Also starting at 16 years old, a child can find themselves in a situation of being an emancipated minor. In this case, they have the same rights as an adult and are recognized as responsible for their actions. They will therefore be able to take out a loan like any person over 18 years old.