As you have asked about the qualification for Income Tax exam, I am giving you information about it, check below for the details

Candidate should be graduated from any university recognized by University Grant Commission.
Graduation could be in any stream.
Candidates must be at least 18 years and not more than 27 years
Maximum age limit will be relaxed by 3 years for OBC candidates and 5 years for SC/ST candidates.

Physical fitness:

a) Height: 157.5cm
b) Chest: 81cm, fully expanded with a minimum expansion of 5 cm

c) Physical Test:
i) Walking: 1600 meters in 15 minutes
ii) Cycling: 8 Km in 30 minutes

Candidate can apply through offline or online
If the candidates prefer offline application procedure, then they should submit the forms at the Regional/Sub Regional offices of Staff Selection Commission after paying Rs. 100/- as Central Recruitment Fee Stamps