To apply for a UK Seasonal Work Visa you first need to complete the online application form. The form is available at the UK government’s website.
You will need to answer several questions related to you, as name & surname, date & place of birth, etc. In addition, there are questions related to your previous trips to the UK or anywhere else in the world. You will also need to give information on the reason you are applying for this visa.
Then you will need to pay the visa fee and the health surcharge. You are exempt from paying health surcharge if you are applying for a UK Seasonal Worker Visa.
Lastly, you will need to find the UK Visa Application Center in your country and there to have your fingertips and photograph taken as a part of your application.