Short answer to your question - On your T2125 Part 4 - line 8811 which is for office stationary and supplies.
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Online access to T2125 Form – HOW to get to and fill out step by step
While you are filing out all your profile questions, and you are not sure if your answer is YES or NO. Simply click on YES and it will open up more information on what you may have to declare. If not, then simply answer NO and move on to the next question. Also this is a guideline "how to" not every question will reflect your personal situation, if not then simply move on to the next steps.
Question Section - Income & work related expenses
Did you work? YES
Did you have expenses related to your employment? YES/NO
I had employment expenses – CHECK if needed
Did you have self-employment income or expenses? Note: Professional income, commission income, farming income, fishing income, and other are all kinds of self-employment income. YES
I have business expenses to claim that are related to earning self employment income. – CHECK (if needed)
Don’t forget to “Enter the province or territory where your business was located. Only enter a province or territory if you had a permanent business set up there.” (If needed)
Did you have other income that you have not yet told us about? Examples include scholastic, foreign, disability, alimony, child support, death benefits, and working income tax benefit payments. YES
I received other income not included anywhere else – CHECK (If needed)
Income Tab – “Self employment” drop down - Your Self-employment Profile for 2017
This opens the T2125 form that must be filled out correctly to ensure smooth transmission to NETFILE. Please make sure that the top part of the form “Identification” section is filled out correctly. Business Name, province, postal code, Industry Code ect...read each section carefully to ensure you are not missing anything needed.
This forms holds all the information needed to declare any independent worker’s time and expenses while performing a duty. Click “Continue” through every section of the form.