Fees charged by the 3rd party can be applied with instructions below.
As for fees charged by Service Canada - I would contact the CRA directly to see if these fees are eligible.
In TTD (download version)
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Easy Step - Income tab - Business Profile Section - follow the screens to bring you to the Expense Section to enter in the amount.
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Formsview T2125 under the Part 4 Expense Section - Professional Advise & Services which is line 8860 in or under "other expenses" line 9270 with a description of the services ie: LMIA
Make sure to keep all receipts and slips in case the CRA requests them.
More from the CRA on each specific line 8860: https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/sole-proprietorships-partners...
And Line 9270: https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/sole-proprietorships-partners...