Try and provide some more context about where on the plant the yellow leaves are? Are they closer to the ground or closer to the top of the plant. Are some leaves turning yellow? Does it happen from the edges? Or between the veins

How many plants do you have? Are they all going yellow? Do your neighbors have peanuts? Are they experiencing the same problem

Have you used any inputs like fertilizer, manure to grow the plants?

Is this your first time growing?