Government mandated pan aadhaar seeding, which means each and every person have to link his or her pan card with aadhaar card or aadhaar card with card otherwise pan card will be blocked and became invalid From July 1, 2017, all tax returns will have to mention the Aadhaar no, as per Sec 139AA of Income Tax Act. If you have both PAN and Aadhaar, you need to link the two. If you fail to do so, your PAN no could become invalid. So if you not yet linked your aadhaar card with pan card or pan card with aadhaar card than do it as soon as possible to not to get your pan blocked in future. If you have not any idea how to link pan card with aadhaar card or how to link aadhaar card with pan card than watch video (click here to watch:  https://youtu.be/HIiUCmiGGtY ) Website which you will have to visit is www.incometaxindiaefiling.gov.in Requirements to link your pan card with aadhaar card is as below:- 1) You should have pan card and aadhaar card 2) Details of pan card and aadhaar c...