There is an old related (but not duplicate) question about automatically replying from an alias email address when an email is received to that alias.
I have a catch-all address, me@example.com, set up using GSuite (free, grandfathered from Google Apps For Your Domain if it makes a difference). I use this to set up individual addresses for different products/companies/etc.
Sometimes I need to send an email from one of those aliases, for example in the situation where Foo, Incorporated will only deal with the registered email address fooinc@example.com for security reasons. I can set up an alias and send an email so that it comes from fooinc@example.com.
However, it's easy to overlook changing the 'send from' address. When composing an email, is there any way to automatically set the 'From:' (send from) address based on the intended recipient? For example, a filter such that any composed email address at a particular domain (eg *@fooincorporated.com) gets sent from a specified alias (eg fooinc@example.com).
A previous answer mentions a userscript (GMail "Send From" Auto Selector), but the answer is from 2011 and neither the script or the answer is currently updated.
Best Answer
What you want is to automatically reply using the alias that received the incoming email? if that is what you are looking for you can check this Gmail Help Center article, it explaines how to add an alias to your account and reply with it https://support.google.com/mail/answer/22370?hl=en. That article is updated so it will work, I hope that helps. Greetings.