Gmail Address Is Used In Everything Associate With Your Mobile Phone.
You can access Google Docs, Sheets, Slides, Calendar, and whatnot in google. The account allows access to other Google applications like Photos, Maps, Drive, Music, and YouTube.
Every application required a Gmail account address, so that’s what Gmail address is.
Yes, You can change the reply-to address in your Gmail account.
Using any browser open your Gmail account. As here we are using Google.com
On the main page of Gmail you will see an option of Setting with a Gear Symbol click on that symbol to open your Gmail setting and then click on the "see all settings" button.
On the Settings page you have an option with the name "Accounts and Import" click on this option/section.
In the Accounts tab you need to go to the "Send mail as:" section where you can see an "edit info" text as shown in the image below. Click on the "edit info" option.
Here, You have a "reply-to" address click on that to forgive your reply-to address. You can refer below image for reference.
Last but not least, now you have to save the changes which u had made. So, just click on the "Save Changes" button in the center as you can see in the image to save your made changes and you are done with the "Change Reply-To Address" process.