hi @raviuppal,
1. There is an error in your html. The <main> element is not closed properly, hence footer is getting cut off. Once you solve this issue, the footer will be full width.
2. This is not possible via custom CSS. You need to make modification to HTML and edit CSS. This is beyond the theme support scope. Please hire a customizer for this.
3. Add following CSS codes to Appearance=> Customize=> Theme Options=> Custom CSS and this should work
.post-69.page.type-page.status-publish.hentry p {
float: left;
width: 50%;
}
4. To show different ads on different page, just post the ad content in Add/Edit page content. If there is some criteria on to how to show ads, you will need to find a developer to make custom plugin for you. This is not achievable otherwise.
5. To get rid of that line, add following CSS codes to Appearance=> Customize=> Theme Options=> Custom CSS and this should work.
#footer {
border-top: none;
}
Regards,
Pratik