Hello Dr Paresh,
Actually, whenever you connect to internet, your security is void. You are always at the risk of some kind of harm like Data theft/privacy/financial being the last.
Coming to question, we can follow best practices to avoid financial fraud.
1. Open a Bank Account with any bank, even Payments Bank which issue debit card.
2. Do not use your primary bank or Card for online transactions on any of merchant website, neither enter Any Card/Login details on any websites.
3. Whenever you need to make online transaction, use Netbanking to transfer required fund to account that you have on Step no 1 and use that card for online transaction.
4. Do not be greedy, never ever enter card details or netbanking details to rerceive Gift Cards/Coupons and Promo codes from untrusted websites/whatsapp forwards etc.
5. Now RBI has mandated all card providors to provide feature to set limits in card and also which kind of transaction to allow or not. Visit your Netbanking or Official Mobile App from your Card-Issuing bank to make necessary changes. For Ex. I only enable International Transactions when I need and after successful transaction, I disable that. In case of any fraud, it will be disabled. Similarly, I set the transaction limit to bare minimum.
Also, always create strong password for Netbanking/Financial application and never use that password on any other websites like Community/Social Network/Education or any other.