SecureString (Password) to String; UiPath RPA

 String plainStr = new System.Net.NetworkCredential(string.Empty, secureStr).Password

Above variable plainStr has the password now. secureStr is the SecureString to be converted. 

https://forum.uipath.com/t/convert-securestring-to-string-get-secured-credential/1704

Include UiPath Library for new version of Studio - 

UiPath.Credentials.Activities