B.Com

Students with B.Com degree have options of doing higher post graduate studies such as M.Com, MBA, MCA or PG Diplomas or LLB, MA Mass Communication. MSW etc. You had also do one year long PG diploma in area of your interests such as Banking, Insurance, capital market, HR, sales etc. You can also do industry specific certifications such as LOMA, IIBA. BCS etc. You can professional courses such as CA, CS, CFA, CMA etc.
CA is very prestigious but difficult to obtain this professional degree. M.Com focuses on commerce, accounting, management and economics related subjects and prepares you for Finance and Accounting jobs in enterprises. MBA is a generic course on business management and administration and it focuses on functional areas of business such as accounting, finance, marketing, human resources, and operations. MBA provides wider options in different functions and various types of industries. Although you must do post graduate degree based on your interest area, I will recommend MBA with Finance specialization for better career opportunities and growth.

Of course, you may pursue these courses together and in-fact, if you belong to commerce background, the Bachelor's degree program must be done along with company secretary course because it will save time and preparation for one will help the other and especially the CS course will help a lot in your B.Com program.
Now, the question arises that are these courses interrelated?
IF not to a very large extent, they are of course interrelated to a certain level. A professional course like CA, CWA and CS, has a professional approach and it helps the student to have a higher level of knowledge in the respective field compared to the regular B.Com courses and it ultimately helps the students of a degree program in the related field.
Here, I am providing you with the syllabus of the company secretary program which might help you to understand better.
Foundation Programme
English and Business Communication
Economics and Statistics
Financial Accounting
Elements of Business Laws and Management
Executive Programme
General and Commercial Laws
Company Accounts, Cost and Management Accounting
Tax Laws
Company Law
Economic and Labour Laws
Securities Laws and Compliances
Professional Programme
Company Secretarial Practice
Drafting, Appearances and Pleadings
Financial, Treasury and Forex Management
Corporate Restructuring & Insolvency
Strategic Management, Alliances and International Trade
Advanced Tax Laws and Practice
Due Diligence and Corporate Compliance Management
Governance, Business Ethics and Sustainability

Here is a list of some of the top law colleges in India:
-National Law School of India University (NLSIU), Bangalore
-Symbiosis Society's Law College (SSLC), Pune
-National Law Institute University (NLIU), Bhopal
-Faculty of Law, University of Delhi
-Banaras Hindu University, Varanasi
-Government Law College, Mumbai
-Amity Law School, Delhi
-Dr. Ambedkar Law University, Chennai
You may check with the law schools in person for the specific course information, eligibility criteria, selection procedure, expenses of the course etc. You could also pursue the Bachelor of Academic Laws (3 years), Bachelor of General Laws (BGL) (2 years), Bachelor of Business Law (BBL) (3 years) which are being conducted by some of the universities, including Annamalai University through the distance education mode. However, these courses are not recognised by the BCI for practice.