Not everyone is eligible for the CTC. And for 2021, the maximum is $500, as it started in 2020 ($250 for 2020 and $250 for 2021):
The 2019 Federal Budget announced the Canada training credit (CTC) which started in 2020. Individuals can accumulate $250 towards their Canada training credit limit each year if, in the preceding year, they met all eligibility conditions. An individual’s Canada training credit limit for a year represents the maximum credit they can claim in that year, and will be reduced in the subsequent year by the amount of any CTC claimed. Eligibility conditions include a minimum working income threshold and a maximum net income threshold in respect of the preceding year. For example, the accumulation of a $250 Canada training credit limit for 2020 was dependent on income in 2019; for 2020 the minimum working income threshold of $10,000 and the maximum net income threshold (the amount at which the 29% tax bracket begins for the 2019 year – $147,667) was applied to a taxpayer’s income earned in 2019.