hello and welcome to hcm forum Bikash,
first of all, i would like to inform you that do not discriminate or underestimated yourself for having a darker skin tone ,
i can understand that you are looking for a job ,but experience and qualifications matter more, do not underestimate yourself.
lightening the skin tone to very fair is not possible but yes it can be brought down by few shades, for that you need to meet a dermatologist
who will analyze your skin first and then let you know the options available for you.
some of the options include, chemical peels
, lasers, and topical creams, but that will be decided by your dermatologist according to your skin type.
i wish you good health.