What is the authenticity of the supplication: "O Allah, if my provision is in the sky, then send it down; and if it is in the earth, then bring it forth; and if it is far, then bring it near; and if it is near, then make it easy; and if it is little, then increase it; and if it is much, then bless it for me"? And is it recited at a specific time?

The supplication (O Allah, if my provision is in the sky, then send it down...) has not been authenticated in the prophetic Sunnah. It is a supplication of a Bedouin woman that Al-Asma'i heard. It is preferable to use comprehensive supplications that combine the good of this world and the Hereafter, with few words but many meanings, such as, "Our Lord, grant us good in this world and good in the Hereafter and protect us from the punishment of the Fire." We have also been forbidden from exceeding the limits in supplication. It is permissible to make this supplication occasionally, without considering it a Sunnah or a constant regular recitation. Some later Shafi'i scholars erred in specifying it for the Duha prayer without evidence.