Reasons are usually mentioned in a loan agreement
The person taking loan usually has to mention in the agreement the reasons for taking loan. It can be taken for any legal purpose such as for purchasing car, for constructing home, for performing marriage and for multiple of reasons.
One of the kinds of loan is personal loan in which parties are not bound to mention reasons for taking loan. Personal loan can be for any purpose and it can be used in any way the borrower wishes to use.