สามีได้ Visa work permit ไปทำงานที London

"Visa work permit" Is it a tier 1 or 2 (General) work visa?
As the main visa applicant (your sponsor), your husband should know how to go about doing that and be the one who MUST find out how to bring his family to live with him in the UK.

Where are you applying from? India or Thailand?

You will need to apply for "a dependant of a points-based system holder visa".

But if you must know, you have to choose the correct visa category from the link below, and go to 'family members' then follow instructions
https://www.gov.uk/browse/visas-immigration/work-visas

For example:

Read the guidance on dependant applications before you apply.  
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/672715/PBS_Dependant_Guidance_01-2018_final.pdf

They’ll also have to pay the healthcare surcharge as part of your application.
https://www.gov.uk/healthcare-immigration-application/pay

Check how much they’ll have to pay before they apply.  (£200/year)
https://www.immigration-health-surcharge.service.gov.uk/checker/type