You can claim the credit when you file your personal income tax return for 2015 and future years.
Each year, you can claim expenses related to work billed for in that year. For the 2015 tax year, you can claim expenses related to work that you paid for, or were billed for (whichever is earlier) between January 1, 2015 and December 31, 2015. For subsequent tax years, you can claim expenses related to work that you paid for, or were billed for, in that year.
Receipts from retailers, suppliers and contractors do not have to be submitted with the income tax return. However, they should be kept in case the Canada Revenue Agency asks for them.