If you’re not in the US (and want to target the US market) or based somewhere that TikTok is unavailable you have a few options:
Many people who want to target the US purchase a US SIM card and utilize it to reach the US. I don’t have direct experience with this, but Guillame on X is a good resource to reference who does this successfully.
Another option is to hire US-based creators who will then have no problem targeting the US. You can source and hire a few different ways: