InterFunnels allows you to host 1 custom domain per funnel.

STEP 1 : Add domain to Account Domains . 

You can add domains by going to settings

CLICK ON "DOMAIN" AND "ADD DOMAIN "

ADD DOMAIN AND ADD IT TO CNAME 

You can add it to your CNAME by following these instructions 

Link : https://www.dynadot.com/community/help/question/CNAME-cPanel

CLICK ON VERIFY DOMAIN AFTER ADDING IT TO CNAME 

STEP 2 : CONNECTING DOMAIN TO YOUR FUNNEL:

Once you domain is verified after that go to your funnel settings and click on Publishing .

Congratulations ! Your Domain  is now added to your funnel