You can change the size with + icon in top left or bottom right
With iTunes, that just switches between full mode and the compact mode. If iTunes is too big for your screen and you can't get to the corner to resize it, go into your System Preferences, change the display resolution to something else, then change it back. iTunes will automatically resize to fit the window.
With iTunes, that just switches between full mode and the compact mode. If iTunes is too big for your screen and you can't get to the corner to resize it, go into your System Preferences, change the display resolution to something else, then change it back. iTunes will automatically resize to fit the window.
How to resize your iTunes window