If you want to do a work placement or internship during your studies you need to make sure you do this in line with your visa conditions.
You can do any work placement during your defined vacation period.
You can do a work placement provided:
If your course does not contain a work placement you could do a placement during your vacation period or for a longer placement of up to 12 months you can convert your degree to a Degree with Employment Experience.You will need to return home to apply for a fresh Tier 4 CAS before you start the placement. There is further information on this requirement here.
You can get help on your options to find a placement from here.