You can use convert an integer to a string in the mapper.
Open the mapper.
In the Target section, highlight the integer element
node to convert to a string.
In the upper far right corner, click to open the Components panel.
Expand Functions > Conversion.
Select the string function and drag it to the target
element node.
A function icon is added to the mapping canvas for the target element node and
the string function XPath expression is added to the
Expression Builder at the bottom of the page.
Drag the source integer node (or you can use a literal) inside the parenthesis
and click the Checkmark icon to save.
For example:
string (12345)
Click Validate.
You can navigate to Test > Generate
Inputs > Execute to see how the XPath
function performs at runtime.