Tagging Fish

I have 5 private lakes withing my community, almost all of them receive
little to no fishing pressure. (Today was memorial day and I was the only
person out fishing or doing anything else on the big lake here), I catch
more than my fair share of Bass on these lakes and was wondering about
tagging bass. Anyone do it? I think it might be cool considering most of the
fishing pressure comes from me. I know nothing about it so a few questions

What effect does it have on the fish if any? Could it harm them?

Any websites that sell tag kits? Any preferred over another?

The reason I ask this is today I caught a fish that I caught a few weeks
ago. I know it was the same fish from a weird black mark on it's tail. It
was caught using the same type worm and caught in almost the same exact
spot. Got me thinking it might be cool to catch a fish that I had caught a
year or two earlier, especially anything with any weight to it, to compare
location/ conditions, technique and lures, Just something I was tinkering
with and figured I would find out more before going forward, any comments
ideas would be appreciated