Legal analysis: the following information should be filled in the special tax deduction form for mortgage: date of filling; Deduction year; Identification number of the taxpayer; Taxpayer information; Location and address of the house; Whether I am a borrower; Provident fund loans; Loan contract number; Term of the loan; Date of first repayment; Lending bank; Withholding agency information; Others. At present, taxpayers can fill in special additional deduction information through the following four channels: 1. Fill it out on the personal income tax APP, fill it out on the website of the natural person tax service platform, fill it out in the tax service hall of the tax bureau, and submit it to the withholding unit for filing in the withholding client software. Personal information such as the taxpayer's name, gender, etc. should be filled in the relevant forms if the mortgage is deducted with a tax; Basic information of mortgage, such as loan method and loan amount; Tax year deducted; And the identity information of the spouse.

Legal basis: Article 14 of the Interim Measures for Special Additional Deduction of Individual Income Tax. If a taxpayer or his spouse uses a personal housing loan or housing accumulation fund of a commercial bank to purchase housing for himself or his spouse in China, the interest expenses incurred from the first housing loan shall be deducted according to the standard quota of RMB 1 000 per month in the year when the loan interest actually occurs, and the maximum deduction period shall not exceed 240 months. Taxpayers can only enjoy a first home loan interest deduction. The term "first home loan" as mentioned in these Measures refers to the housing loan that enjoys the interest rate of the first home loan when buying a house.