Hey! here's a tutorial for how to make Cool Images on the Computer look Even Cooler AND a bit eye-strain-y! wow !! the technique is called Chromatic Aberration, though it's also reminiscent of VHS/80s and 90s TV Aesthetic Edits of characters you might see folks doing!
First things first, you're gonna want to take all the layers in an illustration, and combine them into a single folder, and collapse it. Like so: 
Then you're gonna copy that folder, like so: 
And then you're gonna right click on that Copied Folder, and Merge all the layers within (however your program handles that in its respective menu). Copy and paste that merged layer two more times, for a total of three identical layers. The end result should look something like this 
Create three blank layers between each copy of your flattened illustration, with the blank layers on top of its respective illustration layer. 
Once you've done that, open up your Color Picker to RGB Sliders. On each blank layer fill the entire layer with 100%/255 of one of the three primaries (The order doesn't matter, really, it's a matter of personal preference) 
Set *all of your RGB Color Layers to the Multiply Blending Mode 
Once you've done that, merge the Multiply Layer with the Layer directly below it, the new layer should adjust to a Normal Blending Mode by default, but if not you can change it manually. If you've done it right, your canvas should look a little something like this: 
Next, you're gonna set two of your three layers to the Screen Blending Mode, and leave the layer that is not set to Screen on the bottom of your stack of three layers. This ensures that the colors you chose in the creation of your image stay as accurate as possible when the the other two blending modes apply together. The way it works is pretty magical tbh! Your Layer Menu should resemble this when you're done 
Then, all that's left to do is select a layer, and offset it slightly. The more you offset the layer, the weirder your image is gonna look, and the fuzzier/harder to make out it will be. If you have lined artwork you can also do a very slight Guassian Blur Layer Effect on a Layer to soften up the linework and get that retro feel to your image. The RGB Layer you choose to move will also effect the color of your Chromatic Aberration due to the way things blend. 
(PS. If you want, take the rectangle select tool, and move pieces of a layer or two around to make a fun glitchy effect too, it's neat to play with layers like this! 