What is the best solution and products to use for fungi nail ?

See a dermatologist: Begin with precise diagnosis. Treatment for fungus is effective only if it is actually fungus. Finger or toe? Paronychia? Underlying disease? Different treatment for yeast vs fungus. The pills can be very effective and are generally safe. Once expensive, they are cheap ($10) as generics.

Nothing otc: There are no over-the-counter (OTC) medications that have been proven to cure nail fungus. If you read the labels and leaflets from these products you will see that they can use the nail in their name but not put anything in their literature that it treats that condition. Only laser treatments and prescription topical and oral medications have studies to show cure rates.