Guitar Chords in Major Keys
The guitar chords in Major keys (triads) are a combination of Major, minor & diminished triads [3 tone chords].
The types of chords are the same for all of Western music & instruments when using our modern naming & tuning system.
There are many many ways to apply this information to the guitar. One is to play chord scales either in a fixed position or a linear sequence, or a mix.
Ideally, after studying guitar for a couple of years, we should be able to play any & every chord in all positions (where they exist).

Take Action
Memorize the guitar chords in Major keys - by quality (Major, minor, diminished), the chords are I, IV, V Major, ii, iii, vi minor, viio diminished. Say it fast, think it slow. Know this.
Diatonic means 'within the key' or 'across the tones of a key center'. A chord not in a key (whether, Major, minor, diminished, or augmented type chords) that is not in a particular family (key) of chords is considered nondiatonic. The Blues are a good example of playing in a key, while using nondiatonic chords [save the V chord].
Play fixed position chord scales.
One of the most advanced things we've discovered is that fixed position alphabetical chord scales follow the cycle of forms (CAGED). Ascending, the cycle goes backwards - DEGAC; descending, the cycle goes forward (CAGED). In both cases, a chord form repeats twice in the cycle, depending on which extensions or 'wings' you use. This is the 'holographic' brilliance of standard tuning. This is detailed in lessons within the Lesson Library.
Play linear chord scales. Pick a chord form (CAGED) & play the qualities (Major, minor, diminished) up the neck, linearly.
One way guitar chords can be built - EON
