As conner suggestion, you can able to create document templates by referring this documentation : https://docs.mendix.com/refguide/document-templates.
Refer this one for generating PDF’s using Document Templates in mendix :https://docs.mendix.com/refguide/generate-document. This helps you to generate pdf files in mendix using Document templates.
I’d suggest starting by looking at this area of the documentation: https://docs.mendix.com/refguide/document-templates. A “Document Template” is how you’ll achieve this in Mendix
Hope this helps!
We use this tool to generate documents in Mendix and are pretty happy about it https://appronto.nl/document-generation-for-mendix/