First, go to your Zyte Smart Proxy Manager(formerly Crawlera) Dashboard in Zyte and click the 'Create Account' button:

Next, under the 'Create New Smart Proxy Manager Account', select the regions from where you want to use the IPs and create a new account:

Finally, use the API key for this new user in your project's Smart Proxy Manager Setup page.

Note: creating region-specific extra accounts doesn't entail additional charges.