I am building an online shopping cart (in US) with a payment option to pay a electrum bitcoin wallet address. I will later transfer the bitcoin to an exchange like coinbase, and periodically from there to my bank account.
Why do you need to go to this process on receiving payments to your Electrum wallet address? When Coinbase itself has a
commerce service where you can accept BTC payments directly to your Coinbase wallet and even in your bank account. Coinbase also has a competitor named Bitpay which also offers the same service. Both of them can be good for your setup as website integration will be much easier if you choose either of the services I mentioned. Also you will be incurring additional cost just by transferring your earnings from Electrum to Coinbase because of network fees.