Help with salary withdrawal (pay is in dollars)

Hi guys, I am working for a Contract job that pays me hourly in US dollars into a Deel account. Can anyone help me with the FIRC (Foreign Inward Remittance Certificate) document. When should I get it, can i get it online, is there any other way to get it. Is there any other mode to transfer that is safe to use. Also any idea about the taxability of this income?