How to get a good sound when recording using a microphone.

If you are using using the internal notebook mic, you can improve the result by using an external microphone.

Usually a good microphone requires an audio interface to be connected properly.
However, there are also microphones that comes with an USB connector, so you don't need any adapter.
If you don't have an audio interface, this kind of microphone will have less noise, and better sound, that using a better mic without an audio interface.
Examples:

If you have an audio interface, maybe it's time to upgrade your microphone.
A condenser microphone is the ideal choice. They are used in studios to record vocals.
Examples of not expensive condenser microphones are:

If you already have an external microphone, like the ones used for karaoke, you probably can connect it to your computer by using an adapter like in the picture.
This probably will sound better than the notebook microphone, but will have some noise because of the adapter.

Usually, when you have a good microphone, you won't need to add any EQ to the recording. It will sound good from the start.

Use a Wind screen/Pop filter.

This will prevent the air from the mouth from reaching the microphone, reducing the POP effect when the speaker pronounces the letter 'P'. A windscreen looks like this:

I recommend big windscreens (also called pop filters). They help you keep a proper distance from the microphone. They look like this:

Also, use a microphone stand. You can't do a proper recording if you are holding the microphone with one hand. This will cause changes in the sound as the microphone is moved.

Finally, if you are in a noisy ambience, try to record very close to the mic. And point the back of the microphone to the place where the noise is coming from.
Microphone are usually designed to cancel the sound that comes from the rear.