CRISPR makes gene editing easier, but unless you’ve got a way to deliver it to every cell, it won’t do much unless you’re targeting such a small number of cells that it’s realistic to have a technician physically inject it into a cell.
That would work for an embryo. Ignoring the plethora of ethical issues and the lack of data on long-term effects, it would probably be pretty easy for a scientist to make the change in an embryo and then go through the normal in-vitro fertilization procedure.
For a whole organism, though, it’s more difficult. One obvious solution is a specially modified virus, and that’s under research.
There’s a lot of stuff here if you want to dive deep:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7356196/#sec3-biomolecules-10-00839title
That’s pretty impressive. I hadn’t even thought oral treatments were possible!
It’s amazing.