To apply for a US visitor visa, you need to complete online form DS-160, the nonimmigrant visa application form. You also need to pay a visa fee, schedule an interview, and collect any supporting documentation. Depending on the country where you apply, the process may vary. If you are invited by someone in the US, you may need a letter of invitation from them. If you are eligible for the Visa Waiver Program, you may apply online for an ESTA instead of a visa.

Here are the steps to apply for a US visitor visa:
1. Complete the online DS-160 form and print the confirmation page for each person applying for a visa.
2. Pay the visa application fee.
3. Schedule an appointment for your visa interview at the US embassy or consulate in your country.
4. Gather any supporting documents required by the embassy or consulate.
5. Attend your visa interview at the US embassy or consulate in your country.

For more information on how to apply for a US visitor visa, please visit [US Embassy website](https://uk.usembassy.gov/visas/tourism-visitor/how-to-apply/) .

I hope this helps!