Maybe:
p1 = Plot[x^2, {x, -1, 1}]; p2 = Plot[2 x, {x, -1, 1}];
Grid[{{p1, "Derivative ->", p2}}]
Export["test.pdf", Grid[{{p1, "Derivative ->", p2}}]](*In Windows 10 file is: C:\Users\*.*\Documents*)
or:
Grid[{{p1, Framed@Text[Style["Derivative", Black, Italic, 24]],
Text[Style[Graphics[{Arrowheads[1/2], Arrow[{{0, 0}, {1/2, 0}}]}],
Black, Italic, 24]], p2}}]