How to have different fonts for each section?

1. I asked a general question about using Google fonts and it was excellent. Now i want to know how can i use one Google font for content and another Google font for title and another Google font for sidebar of my website?

This is exactly the same as your previous support question. The same CSS codes are below. The first one targets the post title and the second targets the content. Just change the Font-Family for each to change the fonts used.

.blog-view .entry-title a, .single-view .entry-title a {
    font-family: 'Droid Sans', Arial, Sans-serif;
    font-size: 20px;
}

.blog-view .entry-content, .single-view .entry-content {
    font-family: 'Droid Sans', Arial, Sans-serif;
    font-size: 14px;
}

The first line has

.blog-view .entry-title a

(Which targets the title when on the blog)
and

.single-view .entry-title a

(Which targets the title when viewing a single page)

for sidebar

.sidebar {font-family: 'Droid Sans', Arial, Sans-serif;}

2. Also i want to know is there a way to use one “color of content” in home page and another “color of content” in the post page? They are the same currently. Can i have different colors for them?

Following the sample above:

.blog-view {
    background: #FFF;
}

.single-view {
    background: #FFF;
}

https://www.w3schools.com/css/css_syntax.asp
if you’re using firefox, installing Firebug will help a lot with these things. If your using chrome you could use the inspect element tool(ctrl+shift+i)

Thanks for your help.
1. I am using Firebug but for example now, i want to change background color of home page which is white (#FFFFFF), i have used Firebug and i found that the code is background-color: #FFFFFF;
But now i don’t know how should i place it on Custom CSS. I mean if i place only background-color: #000000; in Custom CSS, the background color of my website will be black? or i should place it as another format?
Please guide me to change the background color of home page.
2. I tried a lot to change the black border that is around the whole site and makes it separate from background but i couldn’t do that. I want to change the color of it. Is it possible? Please guide me.
3. If i want to make the corners of that sidebar as round, how can i do that?
Thanks in advance for your help.

Please guide me to change the background color of home page.

Which part? body background? container background? content background?

Dashboard -> Appearance -> Background

is this what you need?

2. I tried a lot to change the black border that is around the whole site and makes it separate from background but i couldn’t do that.

#container {
    border: 8px solid #000000;
}

Just change the color #000000 to what you need https://www.colorhexa.com/

3. If i want to make the corners of that sidebar as round, how can i do that?
Thanks in advance for your help.

Read more about the border-radius css property.

Great! I got the answers of all my questions. Thank you so much.