Windows have total of four sizes for tiles in start menu which are small, wide, medium and large. You can easily change the size settings by right-clicking on the tiles and clicking on the size you wish to set.
By default settings Windows will display three column of app tiles, only if the tile size is set to medium. If you wish to see more app tiles on the start without scrolling down then you need to either reduce the size or increase the width of the start menu.
The default width of the Start menu can be easily increased by keeping the mouse pointer at the right-edge of the Start menu and dragging the same towards to the right-edge of the screen. But this method adds another three columns of tiles (medium size tiles) to the Start menu and takes more than half the space on the screen on PCs with 14” or lesser screen size.
Add the 4th column to the Start menu
If you want to add just the fourth column in medium size tiles following is the method to do so.
Step 1: Open settings by either clicking on the option in the start menu or pressing Windows logo + I.
Step 2: Click on Personalization.
Step 3: Click Start.
Step 4: Turn on the option which says Show more tiles to add the fourth column.
You can now move existing tiles to the fourth column by dragging and dropping. You can also create custom Start menu tiles.