Everything goes. You can generate great results from either SEO or SEM on their own. SEO is more of a long-term investment. In the long-run, you will get free and sustained traffic. SEM is a tool you can deploy anytime for fast results, but your traffic vanishes when you stop paying.
Of course, using both tools is a great option as there are synergies between them. Digitad has expert teams in both disciplines. Reach out, and we will figure out together what options best fit your projects!