Earlier, it was mandatory for businesses with an aggregate annual turnover of more than Rs. 5 crores to get audit certification from CAs. However, now the CBIC has declared that such businesses can self-certify their GST return. GST returns can be filed on your behalf by a CA and but it is not mandatory for businesses. As GST rules and regulations are many, it is advisable that businesses hire a CA or a software tool that eases the filing process for minimal errors.