Welfare benefits are payments given by the government to certain people on low incomes, or to meet specific needs.
If you have student or short-term student immigration permission (or any other immigration permission with the condition stating ‘No recourse to public funds’ or 'No access to public funds') you cannot claim most welfare benefits.
However, if you have worked in the UK, then you might be able to claim a benefit based on National Insurance contributions (for example, statutory sick pay), or if you are pregnant or have recently given birth you might be able to claim a maternity benefit such as maternity allowance or statutory maternity pay.