For templates created before the 2018/01, when using the editable span option, the field is shown as an input field in the PDF documents. Follow the instruction below to solve the issue.
Problem
Solution
In the top right corner of the Template Builder, switch to Advanced View
In the Home screen, click on Main Flow
Select the Main tab
Scroll to "Document Edit - End" step, click Edit Step
Click on the composeContent command
In the right pane, type false to the editable attribute
Click Main in the top bar to go back
In the top right corner, switch back to Basic View
Now, the editable span in PDF document should carry the same style as the template.
In case you don't want the document to be editable anymore, disable the Enable Editing in your span element.