Use a coloured guide on a slide in PPT 2019-2021

Starting with version 2013 (see my article: Guides in PPT 2013) you can add guides on three levels:

On the slide master (red colour), all the layouts get the guide and all slides based on them
right-click on Master, Grid and Guides, Add vertical/horizontal guide

On the slide layout (orange colour), only the layout gets the guide and the slide based on it.
right-click on layout, Grid and Guides, Add vertical/horizontal guide

On the slide (grey colour),
right-click on layout, Grid and guides, Add vertical/horizontal guide.

You can't move or remove the guides added on the master or slide layout in your slides!

But you can change the colour of the guides.

First add a guide to your slide (see above)
Right-click it.
Choose the Colour option en select your colour.

These guides can be moved or deleted.

If you want to move the guide, position on the guide and drag with your mouse.

If you want to delete the guide, right-click the guide and choose Delete in the quick menu.

You can also drag it off the slide. With a vertical guide to the left or right. For a horizontal guide to the top or bottom.

You can use ctrl+drag to copy a guide. 

Click on the guide you want to copy and hold, you will see a pop-up and with the distance to the middle of your slide. If you do this on the default guide the distance will be 0.00.

Now press the ctrl key, a plus will appear, that way you know you are copying.

Drag and when the desired distance from the middle of the slide is reached release the mouse button then release the ctrl key.

You can use the Alt+F9 combination to view or hide the guides. If you prefer to use the ribbon, click View tab and in de Show group check the Guides box.