Hi, yes you can shift from open university to regular mode after completing your degree no in between changes are allowed. As you have mentioned that you have completed your graduation hence you can change to regular mode. There are entrance exams that you will have to give in order to get an admission in specific college or university. PU CET, CUCET , TUEE , MGU CAT , AUCET , ITM NEST , JNUEE , CPGET (OUCET) these are some of the most popular entrance exams. Hope this helps.