Affinity Designer still lacks some basic functionality, one of them being that there's no 'offset path' option. This is a workaround but only works with positive offsets, it expands the object, I don't think there's a way to create negative offsets.

1. Affinity Photo App
2. Affinity Photo Sale
3. Affinity Photo Offset Printer
4. Affinity Photo Offset Machine

If you want an offset outline then:

1. In this Riding The Edge vlog I demonstrate how I add borders to my images in Affinity Photo.Facebook: https://www.facebook.com/ridingtheedgephotographyInsta.
2. Peter Dam Using layer masks in Affinity Photo is a powerful way to combine parts of several images into a single image or to limit the effect of adjustment layers and filters to only affect a part of your image. Layer masks are nondestructive. This means that you can modify them at any stage of your post-processing workflow.

Affinity Photo App

Affinity Photo The fastest, smoothest and most precise image editing software around, this essential app will revolutionise the way you work, whether you’re editing and retouching images, creating full-blown multi-layered compositions or making beautiful raster paintings. Affinity Photo has become the first choice for photography and creative professionals around the world, who love its speed, power and precision. Born to work hand-in-hand with the latest powerful computer technology, it’s the only fully-loaded photo editor integrated across macOS, Windows and iOS.

1. Select the object you want to apply the offset to (shocking I know).
2. Apply a stroke to the object equal to the offset you want.
3. Convert the stroke to a path, menu Layer>Expand Stroke.

If you want the offset object to be solid and not just an outline then:

1. Select the object you want to apply the offset to.
2. Duplicate it (Edit>Duplicate or Cmd-J/Ctrl-J) as you're going to ruin the original (unless you don't want the original).
3. Apply a stroke to the object equal to the offset you want.
4. Convert the stroke to a path by menu Layer>Expand Stroke.
5. Select the outline and the middle and combine the two objects by menu Layer>Geometry>Add, or do it from the toolbar.
6. You then probably need to move it down a level to be behind the original.

A message from the Affinity team

As a way to lend support to the creative community during these difficult times, we’re once again offering a 90-day free trial of the Mac and Windows versions of the whole Affinity suite, for anyone who wants to use them (even those who have previously completed a free trial). We’re also bringing back the 50% discount for those who would prefer to buy and keep the apps, including our iPad versions.

In other news…

Affinity Photo Sale

our apps are fully optimised for the next generation of Mac

Ready to go on Apple’s Big Sur and primed to deliver superfast performance on Macs with M1 chips, recent updates to the macOS versions of our apps mean huge performance gains.

Affinity Photo Offset Printer

Affinity Photo Offset Machine