Same as the immigrants aren't stealing your job, the greedy capitalist are giving those jobs to immigrants to cut down their bottom line, and they love nothing more when you blame the immigrants.
Immigrants spend less on frivolous bullshit and send money to other countries. Businesses lose out on that end, especially tech companies and wealthy industries.
Manufacturing and manual labor jobs love immigrants because they can pay them minimum wage for horrible working conditions compared to your typical minimum wage 3rd+ generation white worker.
The answer is a) illegally, or b) the company making use of temporary foreign worker programs. The TFW programs have absurdly little oversight and you can generally treat the workers like chattel slaves.