The standard grips this chord is usually shown with.
C# is C#, E# and G#, a major triad. The shape this page opens on is written x43121, lowest string first.

Also written C#maj, C#M or C# major. The same chord either way; which spelling you meet depends on who wrote the chart.
There are 6 common shapes for C# on the guitar, and 46 derived voicings in the triad family.
In which keys. Every note of C# belongs to C# major (the I), Eb minor (the ♭VII), F minor (the ♭VI), F# major (the V), Ab major (the IV) and Bb minor (the ♭III).
The common shapes, written lowest string first: x43121, x46664, 986669, xx6669, 9-11-11-10-9-9, x-x-11-13-14-13.
Triad. Three notes across one string set. C# has xx312x, xxx121, xx3121, 443xxx, xxx664, x4666x, xx6664, x866xx.
The common shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.