Salary Components might not be getting displayed in Income Tax Computation sheet under below-mentioned scenarios:

1. TaxableSalary Components has to be configured as TAXABLE, so, please check the Salary Components configuration whether it marked as TAXABLE.

    Go to Settings >> Salary Components

2. Component Mapping: If exemptions need to be displayed then please ensure whether Salary Components are mapped under 

    Go to Transactions >> Income Tax Compliance >> click on IT Mapping link

And check whether appropriate employees' Declaration has been done