In my Unsubscribe Link app, (yes, that again) the Flow sends out an email from the user running the Flow, which in that case is a Site Guest User. And the email comes from “[Insert Company Name] Site Guest User” which is weird and confusing. I’ve finally googled to learn the secrets of some fields in the Flow “Send Email” Action. And it’s pretty basic and very much a “why didn’t I google this before” moment.
In Flow’s “Send Email” Action, plug in an organization wide email addresses into “Sender Address” and type “OrgWideEmailAddress” in as Sender Type and bob’s your uncle. Want more of an explanation? Keep reading!

Create an Organization Wide Email Address
You do this step outside of the flow. Go to Setup. Search for “Org Wide Email Address” and make a new one or use one you already have. Put whatever you want in the display name. Seriously, whatever you want! Here’s the giant asterix. The email address needs to be a verifiable email address which means the person who owns it needs to receive the email and click a link for you. So if the Second Gentleman is willing to do that for you by all means use his email, KamalasHubby@whitehouse.gov.

You can see above I clearly doctored that image because I don’t really own the email address randy@biscuitbasket.com (yet) so I couldn’t verify it. Oh well. As far as profiles go, in the case of the Unsubscribe Link app, you only need to give the System Admin permission to use it and it works.
Add the Send Email Core Action to Your Flow
Now we’re back inside the flow. Drag the blue Action box to the canvas from the Toolbox or if you’re using Auto-Layout, click the plus to add another element. Fill out your boxes either by typing right in there or by pulling in variables. FYI for Spring ’21, you can use rich text emails from Flow. Thank [swear word] [deity]! In “Sender Address,” type in the org wide email address you created. In Sender Type, type in “OrgWideEmailAddress”. (Do I leave the “.” inside the quotes even though I don’t want you to type that?)

Test It Out
And here is what the email looks like when received. In Gmail when I click the little down arrow, a pop up window expands and I see the email address that I set up and a bunch of gobbledygook.

I think in general this looks great! The alternative is the email will come from whoever is running the Flow. So if these emails are always supposed to come from your Executive Director or Second Gentleman, this is a great solution.
Hello. Within the Unsubscribe Link Screen Flow, do you have to make a new version to edit it? When I tried to edit the Email Address Value, Sender Address value, or add a new action, it wouldn’t let me save the Flow. And then when I added those values and created a new version, the Unsubscribe Email still appeared as the Guest User.
In my new version, I didn’t add a new email element but rather edited the ConfirmationEmail Action in the Unsubscribe Link flow.
Can you let me know where I went wrong?
Hello! With an active flow, you have to “save as” a new version and activate that version. If you deactivate it first, you should be able to click the save button. You are correct that you should be changing the confirmation email element. I will send you an email, to which could you please reply with a screen shot of your confirmation email element! Thanks!
Hello JessieRymph,
We’ve been using your app for a month now and everything works well.
However, we use Salesforce in French and for the Sender Type field I don’t find “OrgWideEmailAddress”, could you tell me the French translation or how to create it?
I’m a beginner user in Salesforce, this is my first installed app, but thanks to your clear explanations, I’ve managed to do everything by my own.
Thanks a lot for your help.
I am sorry but I don’t know!
Thanks a lot for your answer.
You need to set Set Up Organization-Wide Email Addresses, Which you can do by following the steps from this link (https://help.salesforce.com/articleView?id=emailadmin_manage_orgwide_email_addresses.htm&language=en_US&type=0).
Hi Jessie, Great app btw. Its awesome. I tried this on the existing Confirmation Email Action on Unsubscribe Link Flow and activated it as well. Although unfortunately it sends the email as a Site Guest User and my email address.
I also tried removing the Sender Type and still the same issue.
We do have 2 Organisation wide addresses currently and I have used one of them. Would that maybe affect it?
Thanks,
Ruchika
I will have to try this out myself! I will get back to you next week
Hello! I just tried this myself and wasn’t able to recreate the problem. What profiles have access to your Org Wide Email Addresses? That might be a problem. You can email me a screen shot of how you set up your flow jrymph@salesforce.com