I work in US with H1B visa, and I have a joint mortgage with my mother from a Canadian bank on our house in Canada. She is still working in Canada and living in the house. My questions are: can I get the deductions in US income tax from the mortgage interests and the property taxes we paid on the house last year? If yes, all the amount or just half of it? What documents I'll need for these deductions? Thanks for your help in advance!

You CAN claim the deduction for the mortgage and real estate taxes based on the percentage of ownership you have. Hence, if you own 30%, you can claim 30% of the mortgage interest and real estate taxes, all the way up to 100%.

However, if your name is on the title just for estate purposes, i.e. ownership of the house transfers to you on your mother's death and you actually own 0% of the house, then you can claim ZERO percent of the deduction.