HTTP - CRT, KEY and HOST

I’m doing an HTTP integration with a financial institution.

Using Postman I managed to make POST work.

There in postman I have to insert a CRT certificate and the KEY. And I am also obliged to put the HOST.

In make, I didn’t find where to put the HSOT. I’m not referring to the POST URL (endpoint) but to the HOST that the CRT and KEY have.