Hello @Kelvin Pineda,
As of the moment, there isn't an option to change the default email address used when sending your invoices. In the meantime, you'll want to save a PDF copy of your invoice and send it via the personal email you wanted to use.
Lastly, here's an article you can read to learn more about how you can record the payments from your customers: Record invoice payments in QuickBooks Online.
Keep me updated in the comments if you have any other questions. I'll be here to lend a hand.
