This set of string processing actions is completely free and accessible with source code. It is also included in the Workflow Actions Pack, you can use it as separate package
or within Workflow Actions Pack. Complete documentation for string processing actions is located on plumsail.com.
Workflow actions support SharePoint 2013 workflows (Workflow Foundation 4.5). All workflow actions are compatible with SharePoint Online and SharePoint 2013 except Foundation, because SharePoint 2013 Foundation doesn't support SharePoint 2013 workflows (Workflow
String processing actions documentation (external links)
Upload sandbox solution plumsail.wfstringactions.wsp to Solutions Gallery in the root of your site collection and activate it. Then you need to activate Plumsail String Workflow Actions feature on each SharePoint site where
you want to use workflow actions.
Do not forget to restart the SharePoint Designer after installation of workflow actions.
How to upgrade string actions to Workflow Actions Pack.
String actions are compatible with
Workflow Actions Pack, you can use string actions and upgrade to Workflow Actions without recreating your workflows. You just need to deactivate
plumsail.wfstringactions.wsp solution in the Solution Gallery of your site collection, then remove it. Once you removed string actions you need to install Workflow Action Pack. You can find installation guide on