Hi @simeonokwo,
For your existing customer, you must change their role to a wholesale customer role to get the wholesale price. You can export your users to CSV and update the user role in your favorite spreadsheet application. Then import it back.
For your new customer, we have the WooCommerce Wholesale Lead Capture plugin which helps you with on-boarding new wholesale customers more efficiently using the wholesale registration form and puts some of that process on auto-pilot for you.
Best regards,
Fauzan