On guitar most songs can be arranged in easy to play keys using a handful of chords. This doesn’t mean the song will sound exactly like the original but in most cases it will do the job. In music there are 12 keys which are all identical except for the pitch. In other words any song can be played in 12 different keys. E.g. If a song uses the chords C and G this could be considered the 1st and the 5th in the key of C. If you use the chords D (1st) and A (5th) it would sound the same except it would be in the key of D and slightly higher.
Bands like The Beatles, ACDC, Rolling Stones, U2, Metallica, The Eagles, The Police, Queen, Green Day, Bob Dylan, Oasis and many more wrote the majority of their songs using only 3 or 4 chords.
The following is a link explains the 3 chord song concept.
Here are some examples of 3 and 4 chord guitar songs in easy to play guitar keys.
Knockin on Heaven’s door. G, D, Am and C.
Let it be. C, G, Am, F.
Time of your life. G, C, D, Em.
Johnny B Goode. A, D, E.
You shook me all night long. G, C, D.
Yellow. G, D, C, Em.
Sweet Home Alabama. D, C, G.
Stand by me. G, Em, C, D.
Every breath you take. G, Em, C, D.
Wonderwall. Em, G, D, Asus.
Purple Haze. Em, G, A.
Would You Like A Structured Method For Learning Guitar? 5 week Structured Beginner Guitar Course