Do you mind confirming this is set up correctly? I'm having a hard time finding documentation of exactly how to set this up.
The branch substring after - should be some like "1.0.0" and I want to add a V to it so it comes out to "V1.0.0".
I set my smart value up in the image attached.
Thanks so much for reaching out! To answer your question in the title around using strings and smart values in our Create variable action, yes you can!
If you're wanting to if pull the 1.0.0 out of the branch name though, there is just a minor tweak in the smart value that you are using:
Hope that helps!