I got my visa already. Can I travel to uk even without any work permit or a contract?

Answer 1

depends on the the kind of visa you have. If it is a visiting visa, chances are it will be hard to secure a job.
Good luck.

Answer 2

The visa is supposed to help you travel to a specific country. If you need the work permit, it'll depend on whether your visa allows you to work in UK.

Then if it actually does, then you will need to apply for one where you get to UK and have gotten a job. Or you could look for a job first and then apply after wards.