Stretch out a sky
If you want more blue sky above your subject, in Photoshop go to Image>canvas Size. Put 20 % in Height, tick the Relative box, and click the middle-bottom Anchor box. Click OK, then make a thin selection along the top edge of the existing sky using the Rectangular Marquee tool. Press Ctrl/cmd+t to go into Transform mode. Pull the top-middle handle upwards to create headroom.