Choose View > Extras. This command also shows or hides layer edges, selection edges, target paths, and slices.
Place a guide
If the rulers are not visible, choose View > Rulers. Note:For the most accurate readings, view the image at 100% magnification or use the Info panel.
Do one of the following to create a guide:
Choose View > New Guide. In the dialog box, select Horizontal or Vertical orientation, enter a position, and click OK.
Drag from the horizontal ruler to create a horizontal guide.
Drag from the vertical ruler to create a vertical guide.
(Optional) If you want to lock all guides, choose View > Lock Guides.
Move a guide
Select the Move tool , or hold down Ctrl (Windows) or Command (Mac OS) to activate the Move tool.
Position the pointer over the guide (the pointer turns into a double-headed arrow).
Move the guide in any of the following ways:
Drag the guide to move it.
Change the guide from horizontal to vertical, or vice versa, by holding down Alt (Windows) or Option (Mac OS) as you click or drag the guide.
Align the guide with the ruler ticks by holding down Shift as you drag the guide. The guide snaps to the grid if the grid is visible and View > Snap To > Grid is selected.
Remove guides from the image
Do one of the following:
To remove a single guide, drag the guide outside the image window.
For Color, choose a color for the guides, the grid, or both. If you choose Custom, click the color box, choose a color, and click OK.
For Style, choose a display option for guides or the grid, or both.
For Gridline Every, enter a value for the grid spacing.
For Subdivisions, enter a value by which to subdivide the grid.
If desired, change the units for this option. The Percent option creates a grid that divides the image into even sections. For example, choosing 25 for the Percent option creates an evenly divided 4‑by‑4 grid.