tplot1=Plot[PDF[NormalDistribution[],x],{x,-3,3},ImageSize->100,PlotStyle->Directive[AbsoluteThickness[5],Gray],Filling->Axis,FillingStyle->LightGray,PlotLegends->Placed[LineLegend[{"NormalDistribution"},LabelStyle->{Bold,Gray,10},LegendMarkerSize->{15,10}],Above]];
SeedRandom[44];
tplot2=SmoothHistogram[RandomVariate[NormalDistribution[],50],PlotStyle->Directive[AbsoluteThickness[5],Orange],ImageSize->100,PlotLegends->Placed[LineLegend[{"data"},LegendMarkerSize->{25,10},LabelStyle->{Bold,Gray,10}],Above]];

plot1=Plot[PDF[NormalDistribution[],x],{x,-3,3},ImageSize->100,PlotStyle->Directive[AbsoluteThickness[5],Gray],Filling->Axis,FillingStyle->LightGray,PlotLegends->Placed[LineLegend[{"NormalDistribution"},LabelStyle->{Bold,Gray,18},LegendMarkerSize->{35,10}],Above]];
SeedRandom[44];
plot2=SmoothHistogram[RandomVariate[NormalDistribution[],50],PlotStyle->Directive[AbsoluteThickness[5],Orange],ImageSize->100,PlotLegends->LineLegend[{"data"},LegendMarkerSize->{35,10},LabelStyle->{Bold,Gray,18}]];Grid[{{Show[tplot1,Ticks->None],Show[plot1,plot2,PlotRange->All,ImageSize->250]},{Show[tplot2,Ticks->None],SpanFromAbove}},Frame->All,Alignment->{Left,Center}]