How can I use SMTP extension to use my transactional emails

[Sheba]

Using Magento 2.3.3.  SMTP extension is installed using gmail server, meaning emails show the gmail.com address.

How can I still use SMTP, but have it use the appropriate transactional email address entered.  For example, sales@domain.com, affiliates@domain. com, etc.

Thanks for your attention.

[theMageComp]

Hello @Sheba 

I am not sure which SMTP extension you are using but just to let you know, Google login is use to use SMTP server of Google, but sender name and email id can be your own domain email id,

For example, if you are using mageplaza SMTP, they have given one configuration

http://prntscr.com/puio7r Send From.
Those can be configured in Store - Configuration - Sales - Sales Emails.

You can setup the sender name and email there.

[Sheba]

Using Mageplaza's smtp, and yes, it allows for ONE email address.

[theMageComp]

Hello @Sheba 

Oh, I see, you want multiple sender option there in the configuration.

That may need customization in the extension.
You can ask mageplaza or any other Magento agency to work out with this.