Hello, Cat, ¶
I searched for 白话 on the internetlooked up 白话, and I got four different results.

"I searched for 白话 on the internet" is not incorrect, but the way it's phrased isn't common. I looked (something) up is a common way to say this. Also, the internet is really broad- if you used a specific search engine, this would be a good place to put the name of the search engine(s) to replace "the internet". (ex. I looked up 白话 in Baidu)
When addressing someone we put the greeting and the name together. This is especially true for emails.
(ex. Hello John, Hello Anna, Dear John etc etc).

It is a colloquial language formform that we use in our daily life, as opposed to 文言文.

3. It means 空话, or 谎话.

I'm pretty sure this is just a spacing issue, but if this is the 3rd item, the 3 should go in front of this one.

For example, I tell you that I will treat you to a big meal, but I never actually do it, so I am doing 空口说白话.

4. The name of a book written by a Chinese writer.

I hope ithis helps you.

Alternatively "I hope this is helpful."
"This" would be more accurate as the relative pronoun corresponding to your answers,

It is a colloquial language form we used in our daily life, as opposed to 文言文.

It means Cantonese (粤语) .¶
3.

For example, if I tell you I will treat you to a big meal, but I never do it, so I am doing 空口说白话.

The name of a book written by a Chinese writeauthor.