Remuneration of the mandatary
The mandate is presumed to be carried out for remuneration if the services are provided by a professional, but friends or family members are presumed to perform the services without charge.
There is nothing to prevent you, however, from stipulating that a friend or relative receive financial compensation.
The two of you should discuss the matter and make sure everything is clear from the start, since the law will require you to pay the agreed amount.
It is important to realize that you will have to pay the amount whether or not the mandate has been successfully completed, provided, of course, that the mandatary is not at fault.
You can avoid this problem by including a clause in the contract stating that payment will not be made in the event of non-completion.