To configure 3rd Party Viewing of Layouts

Setup the user and the role...

Top menu --> Users --> Staff roles --> + Add a guest role

Role: Custom Layout User

Press OK

Top menu --> Users --> Staff users --> + Add a staff user 

Press + Custom Layout User

First Name: Subscriber Name (Acme)

Last Name: Custom Layout

Username: acmecustomlayout

Make sure there are no spaces in the username.

Select Manual password

Leave the Password as it is

Logon: Enabled

Press Finish

To configure each process...

Top menu --> Setup --> <target process> --> Template tab --> Security

Add a role or group: Custom Layout User

Set the "Custom Layout User" to "Start only, hide all"

Press OK

Verify the setup...

Top menu --> Setup --> <target process> --> Template tab --> Guest user logon + start links

The new acmecustomlayout user should show in the table

To share a specfic layout...

Got the Set Menu for the process and click on the layout you want to be able to share.

Enable Quick Share from Settings.

There are two quick share options, internal and external. Internal quick share is to be used for users. External quick share is to be used for non-users. When you check external, you'll need to select a guest user and select Not hidden for the Security. Sharing layouts externally will allow whoever to access the layout, its information, and be able to save and print it. 

Enabling Quick Share will be shown in Share.

Enabling Quick Share will also allow layout sharing from the mobile app. Below are screenshots that detail the sequence to share a layout.