In the medical world they tell nurses if you didn’t document it, you didn’t do it

Whatever site you use log it

mapymyrun is great for miles. There are strava and trailrunning and others

Beyond the whiteboard is great for crossfit workouts and logging benchmarks

Concept 2 has a forum to log your results and you can join teams or affiliations

Or a simple pen and paper will do (or spreadsheet like i am currently using)