void myfunction() {

...
TCanvas *c = new TCanvas(...)
TH1D *h1 = new TH1D(...) ; // histo 1
TH1D *h2 = new TH1D(...) ; // histo 2

// set stats options (show histo title, nEntries, mean, rms)
gStyle->SetOptStat(1111);

// draw histo 1
h1->Draw(); // draw histo and stats box on default position

// get stats box
gPad->Update(); 
TPaveStats *statsbox = (TPaveStats*)gPad->GetPrimitive("stats");

// get (default) y position of stats box (histo h1)
double y1 = statsbox->GetY1NDC(); // (lower) y start position of stats box
double y2 = statsbox->GetY2NDC(); // (upper) y start position of stats box

// set new position of stats box (histo h1)
double newy1 = 2 * y1 - y2;   // new (lower) y start position of stats box
double newy2 = y1;            // new (upper) y start position of stats box
statsbox->SetY1NDC(newy1);    //set new y start position
statsbox->SetY2NDC(newy2);    //set new y end position

// draw histo 2
h2->Draw("sames"); // draw stats box on default position

// Draw options:
// "same"  : draw histogram on same canvas, do not redraw stats box
// "sames" : draw histogram on same canvas, draw stats box (in default position)

… }