I want to append a string to string type variable.
for build string result in Apply-to-each, Do-Until loop.
1. Notify recent items as a message from Database.
2. Send a message of SharePoint list items as a mail.
3. Send a approve with current task items.
Thank you @gdavenport for workaround.
The workaround of set-variables and compose is nice.
which compose with concat function.
and I hope this idea 'append' for build more easy.