I’m trying to integrate Lob with Integromat/MAKE but I don’t see how to input the merge fields for my template.

To integrate merge variables on Integromat, you need to paste the full HTML string directly into the text box, then use the built-in merge functionality from Integromat to insert variable content. 

This is an example of how that might look:

Note – PDFs do not support merge variables. HTML in Integromat is limited to 10,000 characters.