How do I remove the 'Leave a Reply' form, etc…

When I go to the homepage of my WordPress website:

a: with this URL: https://www.mywebsite.com
then: the ‘Leave a Reply’ form, IS-NOT-DISPLAYED at the bottom of that page…

b: but with this URL: https://www.mywebsite.com/?p=1
then: the form IS-DISPLAYED

NB1: page(b) can also be loaded by clicking-on the ‘Title’ of the first page(a)

NB2: the first page(a) is shown in the Dashboard as a ‘Post’ page, and not a regular-page.

So…
Q1: Why does this happen ?

and…
Q2: how do I prevent the form from being displayed at all…

Q3: Do I have to have the first-page (homepage) as a ‘Post-page’ or can I remove it, and replace it with a regular page ?

I’m using theme: Clean Simple White.

Thanks