There is no way to select the file numbering of the 80D. It only changes a little when certain settings are used.
All still photos are named "IMG0001", etc. when you have sRGB color space. If you instead use Adobe RGB color space, the first character is replaced with an underscore and will appear as "_MG0001", etc.
The suffix changes depending upon the type of file saved.... "JPG" for JPEGs or "CR2" for RAW files. I suppose video file suffixes would be "MOV" or "MP4" (I don't shoot video with my DSLRs, so confirm this, if it's a concern to you).
Within the "DCIM" folder on the memory card images are automatically saved into folders called "100CANON", "101CANON", etc. Each folder can contain up to 9999 images.
You can create custom named folders if you like, with a computer. The first 3 digits have to be numbers between 100 and 999.... but the remainder can be any five letters or numbers you wish. You can change what folder images are saved to, while using the camera. Again, each folder can contain up to 9999 images.
You also can change file numbering to be automatically reset to 0001 whenever a new memory card is installed, to be continuous from 0001 to 9999 (after which it will reset to 0001), or you can manually cause the camera to reset to 0001.
I think all the above info can be found around page 184 of the 80D User Manual.
After the images have been downloaded to your computer, you're free to change the file names in any way you wish.
For example, I change all of mine to reflect the date on which they were taken: YYYY_MM_DD_xxxx, where the last four digits are sequence 0001 to 9999. I also add suffixes to them sometimes, such as subject keywords or other short reminders.
There are any number of software programs that can change file names after download. A free one I've used is FastStone Photo Resizer (which also can re-size photos, add watermarks, and do a number of other batch processing operations):
https://www.faststone.org/FSResizerDetail.htm.
I now use Lightroom to rename my image files.