Music Notation (part 1)
Music notation is a very broad topic. In this article we will focus on one aspect of it: writing and reading pitch (how low or high a note is), and we will of course apply it to the guitar.
The staff
The first thing we need is what we call “music staff”, which is a set of horizontal lines, as the image below shows. 
We use both the lines and the spaces of the music staff, and we identify them by numbers, going from bottom to top. 
The treble clef
Music notation for guitar uses the treble clef, and it will always go to the left of the muis staff. It is a pretty famous symbol, you will probaly recognize it in the image below. 
The notes
Once we have the music staff with the treble clef, we need another set of symbols to have on the music staff. This simbols are the music notes and there is a variaty of them, as shown on the following image.
For the pursposes of pitch, we only need to focus on one thing, the location of the circular section of the music notes. For example, in the next image, all of the notes are A.
The different shapes are used for expressing the duration of the notes, but we will cover that aspect on another article.
Ledger lines
The five lines and four spaces of the music staf are not enough to write all the possible notes that we can play on the gutiar. When we need to have notes higer or lower from those that fit within the lines and spaces of the staff, we just add small lines. This liens are called ledger lines. 
The example above is showing the common maximum of ledger lines we find in music written for guitar on standar tunning. In practice we only use the amount of ledger lines that we need for the specific notes that we want to write, as you’ll see below.
The notes and the guitar
All the natural notes
If the guitar has 19 frets and we have it on standard tuning, these are all the natural notes that we can get. 
An interesting thing with the guitar is that some notes have only one location, others, have multiple. In the following slideshow you will be able to see each note’s possible locations on the fretboard.
The natural notes on first position
At the beginning of the guitar learning journey, we spend a lot of time on the first three frets of the fretboard. It is a good idea to memorize the natural notes in this section of the fretboard, it will enhance your learning a lot.
Here is another way to show the same information.
I hope this has been helpful. Happy practice 🙂