Dual income earner

As the title states. I have a small business selling online. But I've just started working sa BPO. Do I still need to declare my status. May napanuod kasi ako about employers reporting your tax sa BIR. May chance ba na malaman na I'm not registered as a dual income earner? Or ma Audit or something. Sorry po wala akong alam sa ganto. Feel free to educate me.