Composing music is always a balance between including the information needed for the performer to realize your ideas, and leaving enough up to the performer to not stifle the music 1 or insult their intelligence.
For guitar, this is especially tricky because there are (for most of its range) multiple ways to play any given note, and a variety of techniques to achieve certain things.
So you'll see a variety of levels of detail in the notation.
Classical guitar music tends to leave off as much as possible, I think to respect the player's intelligence.
If the composer wants a specific voicing, this is usually done by giving the position number--the fret at which your first (index) finger resides--given in roman numerals.
At this point, there will only be one way to do things.
A number by itself means to just camp your hand there, and a number preceded by a "B" means to barre.
A number with a "C" means to place the capo at that fret, and then after that you can move the hand freely or even barre further up the neck, so there might be multiple symbols in play at once.
1
My biggest complaint about modern avant garde music is how composers, I suppose in an effort to do completely original things, will sometimes write absurdly specific things into the sheet music.
Things I've actually seen include:
Note durations given in time elapsed, with absurd levels of precision (as opposed to the normal relative note durations plus a tempo indication)
An indication for a violinist to bow at a very specific measured distance from the bridge (as opposed to just sul tasto or sul ponticello and letting the player find what they think sounds best) Instruction for wind players to use the wrong fingers.
Not to play with an alternate fingering (which is more reasonable, but still pretty dubious in most situations), but to hold the instrument wrong.
I still have no idea what the point of this was.
The end result is that the poor performers are thinking so hard about the stupid things they're being asked to do that they can't focus on actually playing music , and the result is just dead, awkward sound.
music.stackexchange.com/users/10290/MattPutnam
It will have the notes of let's say a b minor chord and the position will be indicated with Roman Numerals.
You would see a whole slew of notes that fit the B minor chord and you would see an indication of position seven and know it is the minor barre on fret seven.
music.stackexchange.com/users/7306/Neil Meyer
A barre is usually notated above the staff with the letter C (for capotasto ) or B (for barre ) with the fret number in roman numerals.
music.stackexchange.com/users/1344/luser droog
Scores vary as to how much fingering information they contain.
There may be none, in which case the player uses his own judgment and experience.
That applies especially to scores that aren't specifically arranged for guitar.
Notation like CII or BIV is commonly used to mark points where a barre is needed (or suggested) to play that combination of notes.
A horizontal line might be added to mark the length of such fingering.
Other notations may be used as well, such as numbers in circles to suggest a string.
Numbers without circles indicate left hand finger use.
Roman numeral without C or B usually means 'position' rather than barre.
Books normally have a preface explaining the notation.
A barre is also indicated if you are told to use fingers 1 2 3 1 1 for a particular chord or arpeggio.
There certainly is an element of 'if you want'.
Barre notation is part of the fingering help aimed at the student.
Advanced players may be prefer to start with an unmarked score that they can annotate with their own preferences.
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I just want to make sure sure,
if it's a minor chord/major chord, do you >play a major/minor chord?
This question is different from the barre question, which has been well answered above.
So it's worth noting that barre notation has nothing to do with what notes/chords you play.
It only has to do with where and how on the guitar you play them.
If the chord is a minor chord, CV is simply suggesting you play that chord as a barre chord in 5th position (perhaps because you need to go there to play a high first string note, or because it makes an easier transition to or from other notes).
music.stackexchange.com/users/35893/Peter Kirkpatrick
The barre is usually shown by a Roman numeral above the bar/s.
There really is no need for C or B as well, because the RN means nothing else.
Never seen lower case, because the barre sign only means 'play from this fret'.
There is, however, a half- or part-barre sign, which means, as suggested, only barre some strings.
It is C with a vertical line through it, like a cut-time sign.
There is nothing telling whether the chord is major or minor, except the dots themselves, which are self-explanatory, and the direction the piece is moving, sonically.
Usually a good clue in itself.
music.stackexchange.com/users/2808/Tim
How are these barre chords notated on sheet music? Do you just do a barre chord if you want?  I just want to make sure sure, if it's a minor chord/major chord, do you play a major/minor chord?
I'm totally new to classical guitar, I see people playing barre chords
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music.stackexchange.com/questions/39957
music.stackexchange.com/users/25038/Joel
Composing music is always a balance between including the information needed for the performer to realize your ideas, and leaving enough up to the performer to not stifle the music 1  or insult their intelligence.  For guitar, this is especially tricky because there are (for most of its range) multiple ways to play any given note, and a variety of techniques to achieve certain things. Classical guitar music tends to leave off as much as possible, I think to respect the player's intelligence. If the composer wants a specific voicing, this is usually done by giving the position number--the fret at which your first (index) finger resides--given in roman numerals.  A number by itself means to just camp your hand there, and a number preceded by a "B" means to barre. A number with a "C" means to place the capo at that fret, and then after that you can move the hand freely or even barre further up the neck, so there might be multiple symbols in play at once.  Classical guitar music tends to leave off as much as possible in order to respect the player's intelligence.
For guitar, there are multiple ways to play any given note, and a variety of techniques to achieve certain things. Classical guitar music tends to leave off as much as possible in order to respect the player's intelligence. If the composer wants a specific voicing, this is usually done by giving the position number. A number by itself means to just camp your hand there, a number preceded by a "B" means to barre. After that, at this point, there will only be one way to do things. A barre is usually notated above the staff with the letter C or B