Pro tip: Search Google for "teoria musical guitarra" filetype:pdf but add -piano -academic to filter out the irrelevant stuff.
A generic PDF or course will teach you:
Adding the 7th interval for a bluesy or jazzy tension. 5. The CAGED System
You’ve been there. You learn a cool riff on YouTube. You nail the solo. But when someone asks you to play a blues in A or explain why that chord progression works , you freeze.
If you want the absolute gold standard for a practical, useful PDF, I recommend the approach or, specifically for a free downloadable resource, the works by Tobias Hurwitz or the manuals from M.I. (Musicians Institute) .
The Ultimate Guide to Guitar Theory by the National Guitar Academy covers scales, chord construction, and musical keys in a structured format.