The Form 15H is downloadable from the official website of the Income Tax Department. Follow these steps to download:

1. Go to the official website of the Income Tax Department.
2. Click on the ''Forms'' tab located on the left side of the homepage.
3. Scroll down to the ""Income Tax Forms"" section.
4. Select the year for which you require Form 15H.
5. Scroll a few pages further down to find a link to ''Download'' Form 15H.
6. Print and fill in the required details after downloading.

Here is a step-by-step guide to filling out Form 15H:

1. Fill in all the necessary personal information: name, PAN, age, address, and other relevant details.
2. Provide the specific year of assessment for which the declaration is being made.
3. Input the total expected income for the current fiscal year.
4. Provide the total sum of taxable income received for the previous year.
5. Specify the nature of income along with relevant details.
6. Mention the income you are likely to receive for the current fiscal year.
7. State any other reasons for filing Form 15H.
8. End by declaring that the information provided is correct, and sign in the specified fields.

After understanding the purpose of Form 15H, it is important to be aware of the prerequisites to avoid mistakes:

1. Eligibility: Only individuals who are at least 60 years old are eligible to file Form 15H. The total projected income must not exceed the withholding limit.
2. Supplying Accurate Information: All information provided on the form must be accurate. Failure to comply may result in penalties and legal liabilities.
3. Date of Submission: The form must be submitted by the specified date. Failure to do so will result in the deduction of TDS for the entire year.
4. Signatures: The form must be signed by the individual filing it. Unsigned forms will not be considered valid.
5. Correct Information of Income: The declarant must provide complete and accurate information about their income, including the estimated total income, its nature, and value.
6. Submission of the Form: The form must be submitted within the deadline to the relevant financial institution or authorities to avoid TDS deductions.