Hello Aspirant,Hope you are doing well

Yes,you can pursue law course after commerce as as LLB 5 year program can be done after the completion of +2 from any stream. There are various Law schools, in order to get admission in most of the Law Institute one has to appear for entrance examination. The most common entrance exam for admission in LLB program is the CLAT (Common Law Admission Test). This is a all India entrance examination conducted by 14 National Law Schools and Universities for admissions to their under graduate program. To be eligible for the test candidate must have passed the +2 level of exam from recognized board with a minimum of 50% marks [45% for reserved candidates] and must not have crossed the age of 20 years [22 for reserved candidates].
Many private universities will also offer the 5 years Integrated law course where you will dual degree.

For further details Visit this
https://www.careers360.com/courses/llb-bachelor-of-legislative-law

Hope this helps you.
ALL THE BEST