Total noobie questions

Hi!

I was looking to find ways to make more cash back on my mortgage and utilities and such. I'm hoping to find a way to use my double points card with some service to convert it to ACH and I was referred here.

Their website isn't very good at conveying information. What I gather is Bilt is its own credit card?

Can it do ACH payments?

Can I pay my BILT balance with a different credit card, or just my bank?

How much cash back do I get from them?

What are the fees?

Thank you so much! Sorry for the 101 questions, but their own "help" section was tantamount to useless, and I couldn't get any deeper info without first making an account. Also if there are other services to look into I would be deeply appreciative!