As per the CRA "If your royalties are from a work or invention of yours and there are no associated expenses, report the income on line 104". If there were associated expenses, report the income on line 135." Line 135 generates from the T2125, so if you have expenses you use the T2125.
Please view link below from the CRA for more details:
Line 104 - Royalties : https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-re...
