If you want to work in the UK, you will also usually need a work permit. If a company here wants to employ you, it is up to them to apply for the work permit, not you.
In most cases, your husband or wife and any children under 18 who are dependent on you can come with you. However this applies only if you can support them without 'recourse to public funds' (claiming benefits). There are also some restrictions on your family joining you if you are coming here on a temporary work scheme, including:
The immigration rules also say whether you will be allowed to change from one category of entry to another (called 'switching') after coming to the UK. For example:
These rules don't mean the Home Office won't look at your application if you ask for permission to change. But if they then refuse your application, you won't be able to appeal against the decision.