Importance Of Form 26AS: All the employees who pay income tax are definitely aware of Form 16. They know that Form-16 received from their employer is required to file an income tax return. If you get your return filed by a chartered accountant, then they also ask you for Form 16 first. But there is another form, which is necessary to check before filing the return. This important document is your Form 26AS, which is prepared with the Income Tax Department.